Three Approaches to Performance Evaluation
The first approach focuses on employee traits.Trait-rating systems，though declining in popularity，are still widely used，mainly because they are easy and inexpensive to administer.With trait-based systems，certain traits or personality characteristics—“initiative”，“promptness”，“courtesy”，“perseverance”—are identified as essential to acceptable job performance.Supervisors then rate employees on these traits，making a check in an appropriate column—average，good，excellent—for each item;usually there is also space on a form of this type for the supervisor to make freeform narrative comments about the employee(“Fred has had an unusually productive year and played a key role in the preparation of our annual report.”).You are probably familiar with this sort of evaluative instrument，for this is the format that most law schools and other graduate programs(as well as many employers)use on the standard letters of recommendation they require from applicants.
Although they are simple to devise and use，trait-based evaluation systems present serious problems.Even for psychologists，personality traits are slippery commodities.To ask a general manager not only to assess someone's personality but also to make inferences about the effect of that personality on job performance is to invite criticism that the system is invalid，that it doesn't measure what it purports to measure.
Moreover，because personality is，by definition，neither a transient nor an easily manipulated behavior，the prescriptive implications of a trait-based system are unclear at best.When personality is identified—rightly or wrongly—as the cause of an employee's performance problem，what are we supposed to do about it?Employers and employees alike are left with no constructive suggestions for performance improvement.
The second approach seeks to avoid some of these shortcomings by focusing narrowly on employee behaviors.Here we evaluate not the person，but what the person does(a distinction that owes much to child psychology:“Johnny isn't a bad boy，”his mother notes as she surveys the smoking ruins of her house;“he just exhibits bad behaviors.”).In the most popular of the behavioral systems—Behaviorally Anchored Rating Scales，or BARS—for each of the job dimensions identified in a job analysis，one generates a series of statements that describe the behavior—from excellent to execrable—of hypothetical job incumbents.If we were to develop BARS for the secretarial job，we would have to write“anchor”statements for the three job dimensions of typing correspondence and reports，answering the telephone，and operating office machinery.Some examples for the typing dimension would be“uses proper form in typing business letters”，“fails to retain copies of correspondence for office files”，and“frequently misspells words”.
Once arrayed on weighted scales，the statements provide relatively objective points of comparison in the evaluation process.A supervisor simply reads the statements and decides which set best describes the behavior of the employee in question.It is easy to quantify BARSevaluations，with a certain number of points awarded for each level of performance(e.g.，5 for“excellent”，4 for“good”，with each dimension subject to some multiplier that reflects the relative importance of the dimension to the job);once each employee is evaluated on each dimension，a total performance score can easily be determined.
Proponents of the behavioral approach cite not only its relative objectivity but its instructional character as well.By looking at a BARS form or similar instrument，an employee can learn exactly what behaviors are expected and change his or her own conduct accordingly.Because trait-based systems of performance evaluation usually focus on immutable facets of people's personalities，they cannot serve this function.
Still，behavioral approaches are not without weaknesses.They are，to begin with，time-consuming and expensive to design.A good BARS system requires the generation of scores of anchor statements for each job，each of which needs to be carefully validated.And every job class requires a new set of scales:Sets of anchor statements developed for a secretarial job cannot be used to evaluate a welder.Some critics also argue that behavioral systems are too rigid and directive.Not only do jobs change from year to year(even day to day)，but seldom is there one“best”way to do a job，as such approaches seem to assume.The corollary assumption，that what is important is how a job gets done，not what is actually accomplished，clearly misses the point，critics argue.(https://www.daowen.com)
The final approach to performance evaluation responds to these criticisms，at least in part，by focusing on results.Here attention shifts away from the behaviors in which employees engage to the things that they accomplish.Instead of specifying how a salesperson makes contacts with potential customers(“always shines shoes and wears clean shirt”，“seldom returns phone calls”，“keeps accurate records of visits made”)，we would simply ask，“How many widgets did Zander sell last quarter?”If Zander sells a lot of widgets，we are not likely to care much about his sales“behavior”:He is welcome to wear a gorilla suit，speak in limericks，and ride to appointments on a unicycle，as long as sales volume stays high.
The most popular and best known of these results-oriented systems is Management by Objectives(MBO).Although MBO may take various forms，differing in degree of formality，most MBO systems consist of three basic steps:
1.Setting goals and objectives;
2.Working toward the goals and objectives;
3.Reviewing performance.
Although MBO does not logically require heavy employee participation in goal setting，most systems rely on it on the assumption that employees need to“buy in”psychologically.Indeed，heightened motivation and creativity through employee participation and“empowerment”are usually cited as the chief benefits of results-oriented systems like MBO.
Like trait and behavior approaches，result-based systems have problems.Depending on the design of the system，it may be difficult to compare the performance of employees on a common metric.Objectives，after all，will vary with the employee.Therefore，it may be hard to link evaluations to pay and promotion decisions—at least in any way that is perceived as fair.Furthermore，an overemphasis on results may lead to employee confusion and uncertainty about the hows of getting the job done.Worse，it may lead to an“anything goes”philosophy in which ethics and legality are skirted as long as the objective is achieved.Also，results-based systems require special efforts on the part of raters to weigh and filter out extraneous factors—factors beyond the control of the employee—in writing evaluations.