In order to understand the nature of job analysis inferences and how they are validated, it is important to attend to the reasons job analysis are conducted.
Job anaysis have been carried out to determin the tasks and duties performed by job incumbents. Job analysts often write job descriptions which describe the work activites that are performed in the job. This is important in order to be able to identify major job responsibilities for inclusion in a performanc management system or defining the content of training programmes. Job analysis have also been conducted to determine the knowledge, skill and ability needed to perform a given job,including job specifications indentifying that how a job gets done. This is important for extablishing job requirements for personnel selection purposes and developing compensation programmes based on employees' skill levels.
The process of creating job descriptions and job specifications involves three cirtical inferences.
The first inference involves the extent to which a job description and lists of tasks and duties represents the work activities that underlie job performance. Since it concernst the relationship between the work activites that underlie job performance and the manner in which a job is established through an identification of tasks and duties, this inference can be thought of as job descriptive inference. In this inference, the description of tasks or duties represents the physical and mental activities that are performed in the job. However, some of the mental activities performed on the job are not directly observalbe and the jobs are collections of demands with imprecise boundaries. This make it hard to identify where one job stops and another starts. Moreover, a lack of adequate job characteristics taxonomies makes it even harder to decide that whether all relevant aspects of work have been described.
The second inference involves the extent to which a job specification and the KSAOs identified represent the psychological constructs underlying job-related capabilities. This inference can be seen as job specification inference because it concerns the realtionship between the psychological constructs undrlying job-related capabilities. This is the inference that a specification of KSAOs actually represents the psychological constructs need to perform the job. However, KSAOs are not directly observable since the inference relfect psychological contructs. Another difficulties associated with validating this inferenceis that it require a much greater inferential leap than occurs when simply describing tasks or duties when making judgments about KSAOs. This means that inferring KSAOs are more difficult than describing tasks because inferring abilities and other characteristics is much more difficult than inferring knowledge and skills.
Finally, the third inference involves the extent to which the KSAOx are needed to perform job tasks and duties. This inference is...