A Synthesis towards the Construct of Job Performance

Job performance is highly relevant for organizations and individuals alike. Individual Job performance is the behavioural outcome of an employee which points out that the employee is showing positive attitudes towards his or her organization. Job performance is differently defined and measured in different disciplines in different ways. The main purpose of this paper is to define and to review theoretically and empirically the concept of job performance, measurement dimensions of job performance and empirical findings for measurement dimensions of job performance with reference to the various professions in service oriented organizations. As a desk research, this study reviewed literature regarding job performance and its dynamic nature, compared and analyzed dimensions (taxonomies) related to job performance, created a new definition and explained the importance of job performance adding novelty to the existing literature and provided suggestions for further studies.


Introduction
Employee is the crucial one among the other resources in an organization. The success or failure of the organization depends upon the level of contribution given by individuals who are employed in different careers in an organization. In 1920, job performance was simply mentioned as quantity and quality of the output of each employee who is working in an organization. But, in the present scenario employees do much more than traditionally included in their job descriptions. Otley (1999) categorized performance into twofold including organizational performance and job performance. Organizational performance is the major concern of managers as it indicates success of an organization. It considers how well and how far an organization has carried out its activities within a certain period of time. Simply it means that how successful the organization is within a period of time considered. According to Otley (1999), the performance of an organization depends upon the performance of employees and other factors such as the environment, the culture, leadership style and the work environment of the organization etc. The entire value of the individual outcome causes the organizational performance. It seems that the job performance is the smallest unit of the overall achievement of an organization. Therefore, job performance should be an active determinant in achieving the target, goal, mission and vision of an organization stated in the strategic planning process. Borman and Brush (1993) discussed job performance as both direct and indirect forms of employee contribution towards the organizational objectives. Lawler, Mohrman, and Ledford (1992) stated that organizations have started programs such as employee involvement, job enrichment, total quality management, autonomous team work, skill-based pay, and gain sharing plans for the enhancement of competitive advantage in a global economy. The goal of above programs was to increase firm performance by affecting employee behaviours on the job such as taking on increasing responsibility, encouraging employees to change the way they work, and actively contributing to the accomplishment of organizational objectives. Researchers have used alternative names for job performance including "Employee Performance", "Work Performance", "Individual Work Performance" etc. The main objective of this paper is to create a new synthesis to the existing knowledge of job performance revealed by different researchers in the world. Further, it attempts to achieve the following specific objectives: 1. To describe the meaning of job performance reflected from the existing definitions given by different authors.

Dynamic Nature of Job Performance
Due to the changing nature of work and organizations, individual work performance has taken a newer face from traditional views of individual work performance (Ilgen & Pulakos, 1999). In 1995 Howard, as cited in Griffin et al. (2007) discussed two of the major changes; increasing independence and the uncertainty of work system. Campbell et al. (1990) and Murphy and Jackson (1999) stated the necessity of modern measures and they mentioned; "Early approaches to work performance did not account for the full range of behaviours that contribute to effectiveness when systems are uncertain and interdependent". Sonnentag and Frese (2001) highlighted that individual performance is not stable overtime. Variability in an individual's performance overtime reflects on two reasons. They are: 1. Learning process and other long-term changes, 2. Temporary changes in performance. As per, they explained that the nature of job performance is a purely personal related concept which may vary from different types of perspectives faced by individuals. Three types of perspectives of performance were mentioned based on the performance theory. They are: 1. Individual differences perspective, 2. Situational perspective and 3. Performance regulation perspective.
The individual differences perspective focuses on performance differences between individuals. According to individuals' personal capacities including personality, cognitive ability, motivation, and professional experiences may become an impact on job performance. On the other hand, some performance improvement programs such as exploring to specific experiences, training programs enable to enhance job performance of individuals.
The situational perspective refers to the factors in the individuals' environment that stimulate and support or hinder performance. It means that "which situations do individuals perform best?" Job characteristics, role stressor, situational constrains may affect the individual job performance. As a result, new job designing activities can be implemented due to its dynamic nature of job performance.
The performance regulation perspective takes a different look from the other two perspectives. This perspective focuses on the performance process itself and conceptualizes it as an action process. However, this perspective considers organizational level activities for the enhancement of job performance including goal setting, training and job designing, behaviour modification, improvement of action process, feedback intervention etc. Accordingly, job performance can be changed and improved through right identification of its dynamic nature.
Though it is discussed as separated perspectives, researchers often combined two or more of these approaches together to explain employee performance. For example, Barrick and Mount, (1993), suggest a linkage between individual differences and situational perspective. Further, Waldman (1994) also explained a model of performance in relation to individual differences perspective and the situational perspective. According to Waldman (1994), he assumes that both personal factors (individual difference variables) and system factors (situational variables) have an effect on job performance."

Job Performance as a Unidimensional Concept or Multi-Dimensional Concept
As stated above, job performance is not a concrete construct in nature. According to Ghiselli (1956), Campbell (1990), Austin and Villanova (1992), Campbell, McCloy, Oppler and Sager (1993), as cited in Hunt (1996 ), "Job performance is often treated as a unidimensional construct despite a variety of theories and empirical evidence suggesting that it is multidimensional." Campbell (1990) as cited in Johnson and Meade (2010), mentioned that majority of researchers noted that job performance is inherently multidimensional. Hunt (1996) mentioned "the persistence tendency to treat job performance as unidimensional may be due in part to the lack of adequate, empirically developed and tested taxonomies that clearly illustrate different dimensions of job performance." Hence, following part of the discussion is based on how different authors categorized dimensions for measuring job performance theoretically as well as empirically.

Dimensions of Job Performance Based on Different Authors
Burtt ( 1926) and Viteles (1932), as cited in Viswesvaran (2001), have considered both the organizational and individual perspective of job performance for assessment purpose. As a result, both organizational records (objective evaluation) and subjective (individual) evaluation measures have been categorized. The objective measures considered the result based evaluation and subjective measures considered judgment based on personal traits. According to the nature the subjective measures are difficult to decide than the objective measures.
In1944, Toops argued a distinction between accuracy (quality or lack of errors) and quantity (volume of output) as one of the earliest attempts for hypothesizing job performance. As a result, Toops has scheduled measures of job performance into five including 1. Unit of production, 2. Quality of work, 3. Tenure, 4. Supervisory, and 5. Leadership abilities. In 1957 Wherry as cited in Viswesvaran (2001), itemized six dimensions for job performance including 1. Output, 2. Quality, 3. Lost time, 4. Turnover, 5. Training time or promotion ability, and 6. Satisfaction. Moreover, In 1976 Smith distinguished between hard criteria and soft criteria. While the hard criteria were the organizational records, the soft criteria were the subjective evaluation.
In 1980 Schmidt, as cited in Viswesvaran (2001), classified organizational records into direct measures and indirect measures based on the production and personal data. Direct measures of production data included the number of units produced, quality of products in terms of scrap material produced and so forth. Such organizational records are considered more 'Objective' evaluation. Indirect measures depend on human judgment. Individual job performances are considered 'Subjective' evaluation that can be either ratings or rankings such as tenure, tardiness, lateness, accidents, filling grievances, promotion rates and absence etc.
In 1986 Hunter described characteristics that can predict future job performance including 1. Past performance of related jobs, 2. Job knowledge, 3. Psychomotor skills, 4. Cognitive abilities, 5. Social skills and Job related attitudes such as Need for enthusiasm, Stress and control, Achievement. Bernardin and Beatty (1984) also assessed job performance in terms of six dimensions. They are: 1. Quality, 2. Quantity, 3. Timeliness, 4. Cost-effectiveness, 5. Need for supervision and 6. Interpersonal impact.
Generally, performance data were categorized into two groups including judgmental and nonjudgmental measures by Landy and Farr in 1983. Although judgmental methods are more widely used, objective performance indices (for example: production output, scrap rates and time to complete a task) have been useful measures of performance for routine, manual jobs since the 1940s (Rothe, 1951;Rothe & Nye, 1961) and these measures have received renewed attention more recently (Bass & Turner, 1973). Further, other nonjudgmental measures that do not directly measure performance but would provide information on the general health of the organization (for example: grievances, accidents, absenteeism and turnover were considered). Moreover, the following discussion is based on dimensions of job performance which have been used by previous researchers for their studies and few of them are summarized in chronological order.
In 1986 Brief and Motowidlo declared about Pro-social organizational behaviour and the most pro-active behaviours include personal initiatives. Consequently, employees show personal initiatives when t heir behaviours fit an organization mission, when their goals have a long-term focus, and when they are capable of finding a solution for the challenging situation. The easy way to identify the forms of pro -social behaviour is observing the acts of members such as helping, sharing, donating, and volunteering. According to them, "pro-social organizational behaviour is: 1. performed by a member of an organization, 2. directed towards an individual, group or organization with whom he or she interacts while carrying out his or her organizational role, and 3. performed with the intention of promoting the welfare of the individual, group or organization towards which it is directed" (Brief and Motowidlo (1986), as cited in Hazzi & Maldaon in 2012).
Thirteen types of pro-social organizational behaviours were specified by Brief and Motowidlo in 1986.  1. Altruism-an employee's tendency to help other co-workers in the firm with their work (helping behaviour).

2.
Conscientiousness-an employee's decision to do the job by compliance to organizational norms and the need to surpass formal requirements 3. Civic virtue -when an employee participates responsibly in matters pertaining to the organization's political life. 4. Courtesy-prevention of problems arising from work relationship and treating other co-workers with respect.

5.
Sportsmanship-an employee's reaction to trivial matters by not complaining and maintaining a positive attitude.
In 1989 Murphy elaborated four dimensions of job performance such as: 1. Task oriented behaviour: accomplishment of duties and responsibilities of someone's job.
2. Interpersonally oriented behaviour: represented by any interaction the focal employee has with other employees. This can be task related and non-task related behaviours including cooperating, communicating, exchanging job related information.
3. Down-time behaviour: employees engage in during their free time either at work or off-site.
(for examples. outside behaviour that causes lateness, absences) 4. Destructive or hazardous behaviour: Non-compliance with rules, violence on job, theft and other behaviours counterproductive to the goals of the organization. Campbell et al. (1990) proposed a general latent structure of job performance with eight performance components. They are: 1. Job-specific task behaviours: behaviours that an individual undertakes as a part of a job 2. Non -job -specific task behaviours: do not pertain only to a particular job 3. Written and oral communication behaviours: include formal and informal oral and written presentations to various audiences in many different jobs in the work force 4. Demonstrating effort: consistency or perseverance and intensity of the individuals to complete the task 5. Maintaining personal discipline: individual would be expected to be in good standing with the law 6. Facilitating peer and team performance: acting as a good role model, coaching, giving advice or helping to maintain group goals 7. Supervision or leadership position: responsible for meeting out rewards and punishments. These aspects of performance occur in a face to face manner 8. Management or administration: setting organizational goal or responding external stimuli to assist a group in achieving goals of organization.
In 1993, Borman and Brush discussed employee performance based on two basic dimensions including: 1. In-role work performance

Extra-role performance
In-role work performance involves activities that are related to employees' formal role requirements (Borman & Motowidlo, 1993). According to Brown (1996), generally it is believed that job involvement, by positively affecting employees' motivation and effort, leads to higher level of in-role job performance. Williams and Anderson (1991) described "In-role performance as the work behaviour that is related to duties and responsibilities that are formally specified in the employment contract." Extra role performance involves certain behaviours of employees which are not part of their formal job requirements as they cannot be prescribed in advance for a given job but they help in the smooth functioning of the organization as a social system (Bateman & Organ, 1983). This type of behaviour is called as organizational citizenship behaviour and it can be divided into two categories.
The first is the 'organization-oriented citizenship behaviour', for example, adhere to the informal rules that aim at maintaining the work orders, when one cannot go to work, he or she will ask for leave in advance etc. The other category is 'individual-oriented organizational citizenship behaviour'. For this category, the direct purpose of the subjective behaviour is to benefit the individual, but it indirectly contributes to the organization by this way and examples are help absent colleagues to complete the work, interpersonal assistance. The organization-oriented citizenship behaviour is labeled common obedience or compliance, on the other hand individual-oriented organizational citizenship behaviour is labeled altruism.
In1993 Borman and Motowidlo also considered performance as a multi-dimensional concept through a twofold categorization: 1. Task Performance

Contextual Performance
Task performance is "the proficiency with which job incumbents perform activities that are formally recognized as part of their jobs; activities that contribute to the organization's technical core either directly by implementing a part of its technical process, or indirectly by providing it with needed materials or services" (Borman & Motowidlo, 1993). They believed that the contribution should be included in task performance; direct (for example; in the case of production workers) or indirect (for example; in the case of managers or staff personnel). It is highlighted two central features of task performance that are formally recognized as part of the job and contribute to the technical core. Murphy (1989) defined task performance as "the accomplishment of tasks within an incumbent's job description." Further, in recent years paid attention to specific aspects of task performance such as innovation and customer oriented behaviour become increasingly important as organizations put greater emphasis on customer service (Anderson & King, 1993;Bowen & Weldman, 1999; as cited in Sonnentag & Frese, 2001).
Contextual performance is also not a single set of uniform behaviours. Van Dyne and Lepine (1998) mentioned it as a multi-dimensional concept. Moreover, Motowidlo and Van Scotter (1994), Borman and Motowidlo (1997), Hattrup, and O' Connell, and Wingate (1998), as cited in Sonnentagand Frese (2001), mentioned "Contextual performance is predicted by other individual variables, not only task performance. Abilities and skills tend to predict task performance while personality and related factors tend to predict contextual performance." Not only having the above basic category of task and contextual behaviour of job performance, but also Hunt (1996) proposed "Generic work behaviour" as taxonomies of job performance. It is defined as behaviour that contributes to the performance of virtually any job independent of technical job roles. Eight specific dimensions of generic work performance have been suggested through a specific analysis of employee behaviours in retail settings. These dimensions were; 1. Industriousness, 2. Thoroughness, 3. Schedule Flexibility, 4. Attendance, 5. Off-task behaviour, 6. Unruliness, 7. Theft and 8. Drug misuse.
In 1996 Viswesvaran, Ones, and Schmidt suggested that context of job performance includes ten dimensions. They have categorized ten dimensions using a content analysis and conceptual grouping including 1. Productivity, 2. Effort, 3. Job knowledge, 4. Interpersonal competence, 5. Administrative competence, 6. Quality, 7. Communication competence, 8. Leadership, 9. Compliance with authority, and 10. Overall job performance. Afterward, in the early 2000s Viswesvaran and ones have categorized job performance into three broad dimensions including 1. Task performance, 2. Organizational citizenship performance, and 3. Counterproductive work behavior (Koopmans et al., 2011). Pulakos et al. (2000) paid attention towards the dynamic nature of the environment and discussed another perspective of job performance. They highlighted the necessity of the concept of "Adaptive performance". Different authors have applied different names for adaptive performance such as Neal and Hesketh (1999), Pulakos et al. (2000) referred as "Adaptive performance"; Murphy and Jackson (1999) "Role flexibility". London and Mone (1999), as cited in Pulakos et al. (2000) used the term "Proficiency of integrating new learning experiences" Pulakos et al. (2000) have conducted a wide literature review and factor analysis. They have suggested an eight dimensional taxonomy for adaptive performance including: The idea presented by Pulakos and co-workers suggested that more empirical research is needed for increased importance of adaptive performance. Having a special attention on adaptive performance, Stokes (2008) has done a convergent and predictive validity of adaptive performance. A Venn diagram has been created to review the amalgamated view of the leading job performance model. Figure 1shows this diagram and it mentions the nature of relationship among each dimension of job performance which has been mentioned by different scholars. The Figure 1 includes three types of job performance domains. It is considered job performance an integrated model of three models introduced by Campbell et al. (1990), Borman and Motowidlo (1993), and Pulakos et al. (2000). Thus, it is too difficult to bring job performance clearly into a common category due to its subjective nature. It also provides proper evidence that there is no any reciprocal categorization of measurement dimensions of job performance. In accordance with Campbell (1990), Borman and Motowidlo (1993), it is mentioned that due to lack of unifying theoretical framework, job and non-job dimensions have been introduced by scholars. Hence, the above Venn diagram is important to identify the integrative nature among the different dimensions of job performance. However, the above figure emphasizes that there are no precisely defined categories for measuring job performance. One can use job performance dimensions as separate domains or a combination of more than one category together. Rotundo and Sackett (2002) discussed three main performance dimensions under the general performance factors including: 1. Task performance 2. Citizenship performance

Counterproductive performance
Task performance occurs when employees perform actions that transform raw materials into goods and services. It is the most obvious form of contribution to an organization, because it represents behaviours that directly produce goods and services. In most organizations, a very large portion of employee effort is spent on task performance. Hence task performance is the "proficiency with which job incumbents perform activities that are formally organized as part of their jobs; activities that contribute to the organization's technical core either directly by implementing a part of its technical process, or indirectly by providing it with needed material or services" (Borman & Motowidlo, 1993). Task performances are divided into two parts: 1.Declarative knowledge, and 2. Procedural knowledge and skills (McCloy, Campbell & Cudeck, 1994). Declarative knowledge understands of what needs to be done to perform certain tasks. Under the procedural knowledge and skill, it is concerned the ability to perform the prescribed tasks. Therefore, the employee must know 'what to do' and 'how to do' the activities to perform an assigned task.
Citizenship Performance contributes to organization by building a positive organizational environment. This concept considers "behaviours of a discretionary nature that are not part of employees' formal role requirements, but nevertheless promote the effective functioning of the organization" (Organ, 1988). Therefore, employees are good citizens when they willingly go beyond minimum expectations to cooperate and help others, for example, Pulakos et al.'s (2000) Adaptive job performance Job performance domain Borman & Motowidllo's (1993) Task & Contextual performance Campbell et al.'s (1993) Eight-factor model volunteering to take on tasks that are not part of one's job.
Two major parts of citizenship behaviour are Organizational citizenship behaviour and Interpersonal citizenship behaviour (Scott & Judge, 2009). Employees engage in organizational citizenship behaviour when they do such things as protecting the organization's property, giving advance notice when unable to come to work, and following informal rules that help maintain order etc. The interpersonal citizenship behaviour is positive employee actions aimed at helping specific co-workers succeed. Such behaviours include taking time to listen to co-workers' problem, passing along information to peers, and helping people who have been absent etc.
Counterproductive performance is harmful to the organizations and its employees. Rotundo, et al. (2002) mentioned this as "it is non-task behaviour that has negative consequences for organizations and as well as employees". Due to such a circumstance, lower productivity is to be created (Dunlop & Lee, 2004). Counterproductive behaviour is also directed towards either the organization or specific individuals.
According to Robinson and Bennett (1995) these two dimensions are categorized into four distinct categories including production deviance, property deviance, political deviance and personal aggression.
While the production deviance and property deviance actions are directed towards organization, other two are directed towards interpersonal behaviour. Production deviance is considered as harmful employee actions aimed at reducing the speed and accuracy of production process such as taking unauthorized breaks, intentionally working slowly, wasting company resources etc. However, the more serious is property deviance which includes actions that destroy the assets of an organization such as sabotage of equipment, misuse of expense accounts or steal materials and products. Further, they defined the political deviance as harmful actions that are designed to harm the performance and career of the other employees such as gossiping about co-workers, showing favoritism, and competing with others in non-beneficial ways. However, more serious form of counterproductive behaviour directed toward individuals is personal aggression which is presented by unsympathetic acts including violence and sexual harassment.
In 2011

Counterproductive work behaviour
This study used 123 indicators for the measurement process of the construct. The following sub areas show how they defined each dimension and used indicators to measure these dimensions.
Task Performance was defined as central job tasks which are assigned to employees. Accordingly, Koopmans and others included job knowledge, work quantity, work quality, keeping knowledge up-to-data, job skills, working accurately and neatly, planning and organizing, decision making, administration, solving problem, oral and written communication, monitoring and controlling resources under the category of task performance.
Contextual performance was referred to employee behaviour that supports the organizational, social and psychological environment in which the central tasks are performed. They included effort, initiative, attention to duty, enthusiasm, resourcefulness, motivation, dedication, persistence, proactivity, creativity, corporation with and helping others, communication, politeness, interpersonal relations and organizational commitment.
Adaptive performance was referred to an employee's proficiency in adapting to changes in a work system or work roles. It included adjusting goals and plans according to situation, generating new innovative ideas, learning new tasks and technologies, understanding other groups or cultures, being flexible and open minded towards others, showing resilience, quick analysis, remaining calm, and acting appropriately.
Counterproductive work behavior was considered as harmful to the well-being of the organization. It included off-task behaviour, presenteeism, too many or longer breaks, absenteeism, doing task incorrectly, complaining, tardiness, accidents, insulting or gossiping about co-workers, fighting or arguing with co-workers, misusing privileges, theft, dis-regarding safety, aggression, and substance abuse. Koopmans et al. (2011) have conducted their study for determining constructs of individual job performance in relation to different research fields, including occupational health, psychology and management. Therefore, it can be considered as a massive study and their heuristic framework is generalizable to all types of job. They have collected many of job performance related dimensions which have been used by previous scholars and all those dimensions have been categorized into above four. Further, they have proposed to conduct empirical studies for future researchers associating with different types of jobs. As a result of the above findings, taxonomies that have been used in earlier stage up to the present were reviewed. It shows that different scholars have used different measures for measuring purpose of job performance due to its complexity. (Source: based on literature) *1. Brief and Motowidlo, (1986), 2. Organ (1988), 3. Murphy (1989), 4. Campbell et al. (1990, 5. Borman and Brush (1993), 6. Borman and Motowidlo (1993), 7. Motowidlo and Van Scotter (1994), 8. Motowidlo (1997), 9. Hunt (1996), 10. Viswesvaran and Ones (2000), 11. Pulakos et al. (2000), 12. Rotundo and Sackett (2002), 13. Stokes (2008), 14. Koopmans et al. (2011).
As a result of the discussion summary depicted in Table 1, up to year 2011 different types of job performance dimensions have been applied for measurement purpose. It shows that there is a remarkable trend and widely used dimensions have appeared. 42% of authors of the Table 1 consider that task performance is widely used dimension for measuring job performance and 35% of authors have used contextual performance as an important taxonomy. Other widely used job performance dimensions are adaptive and counterproductive work behaviour and citizenship behaviour. According to above evidences materialized from literature, task performance and contextual performance should be the most popularly used dimensions for measuring job performance. Furthermore, literature findings provide evidence that there are incalculable dimensions in literature for measuring job performance and some researchers have given different names for similar measures. Therefore, there is a possibility to amalgamate different dimensions in Table1 subjected to reasonable evidences.
For example, "t ask performance", "job specific task behaviour" and "in role work performance" can be considered under the same category. Murphy (1989) elaborated task performance as "the accomplishment of tasks within an incumbent's job description". Williams and Anderson (1991) explained "in role work behaviour related to duties and responsibilities that are formally specified in the employment contract." Further, Campbell et al. (1990) measured job performance as prioritizing to the job specific task behaviour. They considered that job specific task behaviour as "a part of formal job of employee." The other example is that "organizational citizenship behaviour", "extra-role behaviour", "non-job specific task behaviour" and "contextual behaviour" can be incorporated to the same category. Of course, Batman and Organ (1983) explains that the extra role behaviour which is not a part of the employees' formal job and this type of behaviour is called "organizational citizenship behaviour." Further, non-job specific behaviours do not pertain only to a particular job . Motowidlo and Van Scotter (1994), Borman and Motowidlo (1997), Hattrup, O' Connell, and Wingate (1998) mentioned that abilities and skills tend to predict task performance while personality and related factors tend to predict contextual performance.
Besides, "destructive or hazardous behaviour" of Murphy can be merged with the "counterproductive work behaviour". Of course, counter productive work behaviour relates to non-task negative consequences for organization as well as employees (Rotundo, 2002). Murphy (1989) provides the same meaning and explains "destructive work behaviour" compliance with rules, violence of job, theft and other behaviours counterproductive to the goals of the organization. As a result of the above review, taxonomies of job performance are reasonable to categorize generally into three such as task performance, contextual performance and counterproductive work behaviour.

Dimensions of Job Performance Related to Specific Professions
The above analytical part reviewed and prioritized the job performance domain for general usage. Following part of this paper is expected to review the taxonomies of job performance that have been used in recent studies for different professions representing service sector organizations. According to Chang and Chen (2006), Jung and Jung (2001) as cited in Sani et al. (2013), "performance could be indicated by assessing employees' workload where the determination of workload plays an important role in designing and evaluating an existing man-machine system". The workload may not be similar in different occupational settings. Following empirical findings in Exhibit 2, show selected evidence for the synthesis of job performance used by researchers recently associating with the selected specific job positions including service sector employees. The above Exhibit 2 shows recent empirical findings of job performance measurement dimensions which have been used by different authors to measure job performance of different professions. Among them, there are managers, teachers, lecturers, IT professionals, office staff members, and retail employees. According to each profession, dimensions of job performance diverge. It is evident for multidimensional nature of job performance. On the other hand Exhibit 2 provides evidence for the customized nature of performance measures. Adding further, Austin and Villanova (1982), as cited in Welbourne et al. (1998) highlighted that lack of generalizability of the performance criteria hinders the validity of many predictors of job performance. Eventually, it can be noted that job performance is normally conceptualized as actions and behaviours that are under the control of the individual that contribute to the goals of the organization. Hence, dimensions may vary according to job tasks, work circumstances, personal traits, organizational environment etc.

Importance of Job Performance
It is indeed a critical organizational phenomenon owing to several value motives or reasons which are presented as follows: i. Job performance is one of the most extensively researched phenomena.
ii. Job performance works as an outcome or a consequence of many variables in many of studies.
iii. Job performance can be considered as an intervening variable.
iv. Summation of individual performance makes organizational performance or business performance.
i. Job performance is one of the most extensively researched phenomena. There are lots of theoretical and empirical studies which have been conducted in relation to job performance. As evidence, this paper has reviewed many theoretical and empirical findings above in Table 1 and Exhibit 2. Furthermore, according to Arvey and Murphy (1998), Campbell (1990), Austin and Vilanova (1992), Schemidt and Hunter (1992), Murphy and Cleveland (1995), as cited in Viswesvaran (2001) job performance is an important 'Construct' in industrial or organizational psychology. Sonnentag and Frese (2001) conducted a desk research and found 146 research findings during the past 20 years. As a result, they found that 54.8% of literature sources considered individual level performance as a 'Core-construct'.
ii. Job performance works as an outcome or a consequence of many variables in many of studies. Schmidt and Hunter (1992) mentioned that Job performance is the most important 'Dependent Variable' in industrial work and organizational psychology. A desk research conducted by Sonnentag and Frese (2001) reveals that majority of the sample (72.5%) addressed individual level performance as a 'Dependent variable' or 'Outcome measure'. As per researchers namely Beh (2011), Shekari et al. (2014, Hettiarachchi and Jayarathna (2014), Muindi et al. (2015), Rai and Tripathi (2015), Hafeez (2015), and Philippaers (2016) have conducted studies and measured job performance as a dependent variable.
iii. Job performance can be considered as an intervening variable. It means that there is a causal link between both individual perspective as well as the organizational level perspective. Accordingly, job performance should be linked with employee ability, traits, motivation, education, job knowledge and skills etc. Due to the variation of those factors, job performance may be varied by person to person. On the other hand it affects to the overall outcomes of the organization. It means that the consequences (results) of job performance are productivity, customer retention, customer satisfaction, growth of sales etc.

iv. Summation of individual performance makes organizational performance or business performance.
Individual performances determine the performance of the organization as a whole (Hitt et al., 1979). Sum of individual job performances in all departments of an organization will become organizational performance of that organization. Rounok and Parvin (2011) emphasized that skilled, qualified, and motivated workforce contributes a lot to achieve the organization's success. Hatane (2015) mentioned that organizational performance includes both financial and non-financial performance. Job performance is also considered under the subjective and objective forms or quantity and quantity forms. Hence, the overall individual performance directly relates to business performance. Newstrom and Davis (1997), shows the relationship between ability and organizational results emphasizing the importance of individual contribution to the organizational outcomes.
Exhibit 3. Individual contribution for organizational results 1. Knowledge x skill = ability 2. Attitude x situation = motivation 3. Ability x motivation = potential human performance 4. Potential performance x resources x opportunity = organizational results (Source: Newstrom and Davis, 1997) As a result of the above matters it is clear that the interaction among the individual characteristics and characteristics of the situation causes individual performance and it is the base for organizational results.
It is possible to mention here another motive for considering job performance as critical. Importance of job performance can also be presented when purposes of evaluation of job performance are considered. In organizations evaluation or appraisal of employee job performance is done at least once a year (Opatha, 1992). According to Opatha 2013, evaluation of employee job performance has a variety of utility and serves as a summative function (to assist in making equitable and effective personal decisions such as salary increments, incentives, transfers and disciplinary actions); a formative function (to improve employee current and future performance by identifying strengths and weaknesses and accordingly by training and developing); and an informative function (a communication to the employee dealing with upward and downward communication for self-motivation and self-development).
Moreover, Cascio (1991) categorized the purposes of job performance into three; including 1.administrative purposes to the organization, 2.Feedback purpose to the individuals and 3.Research purpose for deciding validation of selection techniques or efficacy of training etc. DeVries et al. (1986), as cited in Viswesvaran (2001), noted that the uses of job performance assessment in Great Britain can be categorized into three; 1. To improve current performance, 2.To set objectives, and 3. To identify training and development needs. As per, Viswesvaran (2001) reviewed the results of different researchers and noted " in 1970 in both United States and the United Kingdom indicated the prevalence of the job performance assessment for the purpose of making administrative decisions". The above findings show supportive evidences towards the different usages of job performance results.
With reference to the above, it is clear that job performance is a more important construct on behalf of employee perspective as well as employer perspective. Hence, it is worth to create our working definition for job performance as follows.
"Job performance is the extent to which the employee has shown his or her traits, engaged in behaviours and produced results which are appropriate to task performance, and has engaged in citizenship performance and counterproductive performance during a particular period of time." As a result interaction of individual characteristics and characteristics of the situation, employees may behave differently. Hence, traits and employee behaviours are more sensible for job performance. On the other hand, it is needed to consider how individuals contribute towards the organization. It means that measures should be linked with output of individuals' work. Accordingly, employee behaviour that directly contributes to producing goods or services is labeled as 'Task performance' and employee behaviour that helps others and creates a positive work environment is labeled as 'Citizenship performance' and harmful employee behaviour that is labeled as 'Counterproductive performance'.

Conclusion
Every organization performs its task with the help of its resources. Among the resources manpower is the live resource that utilizes other non-living resources for maximum level of output. The human resource is critical and difficult to manage because human behaviour is highly unpredictable. It differs not only from individual to individual but also on the part of same individual at different points of time. In spite of biological and cultural similarities, human beings not only differ in their appearance but also in their capabilities and competencies based on their living background, training, experiences and personal qualities etc. With the aim of reviewing literature of job performance, this paper focused on six objectives. The first objective was to define job performance according to different authors. They were careful to define job performance based on job, job tasks, personal qualities and existing circumstances. Secondly, the paper discussed the dynamic nature of the concept of job performance and reviewed both personal and system factors which may affect its dynamic nature. Thirdly, this paper reviewed different taxonomies of job performance in chronological order and it is concluded that job performance is a multidimensional concept. As a result, the selected twenty dimensions of job performance were compared among selected authors and these dimensions were summarized based on their usage. Hence, the forth objective was achieved having found widely used job performance dimensions that are task performance and contextual performance based on literature comparison. As the fifth objective, recently used dimensions of measuring job performance were found from recent empirical findings that have been done in service sector related organizations. It reviews that researchers have unquestionably used different dimensions for measuring job performance for different professions based on their requirements. Finally we reviewed that there are numbers of specific dimensions which have been categorized yet, researchers face difficulties in applying clear-cut measurement dimensions. Though this study is a desk research, it reviewed well the construct of job performance, dimensions and did a comparison among the researchers and created the working definition for job performance and suggested more appropriate measurement dimensions for measuring job performance. Further, empirical findings were reviewed based on different occupations in service sector organizations. It is also discussed four motives under the importance of job performance adding novelty to the existing literature. Finally, we recommend that empirical studies must be done specially for job performance of diverse employee work groups in diverse careers associating with service sector in different organizations in different countries.