Q1.  What is validity generalisation in the context of ability testing?

Validity generalisation is a significant concept within ability testing, as it pertains to the degree to which a test's validity, or its efficacy in forecasting job performance, can be applied across diverse job settings, industries, and demographics (Schmidt & Hunter, 1998).  The importance of this concept lies in its support of the idea that a thoroughly validated ability test can reliably predict job success in a variety of contexts, as opposed to being restricted to a specific job or organisation (Salgado et al., 2015).

In essence, validity generalisation implies that if an ability test exhibits robust predictive validity for a particular job or demographic, it is probable that the test will be equally effective in predicting performance for similar positions or demographics (Schmidt & Hunter, 1998).  This enables employers to confidently utilise standardised ability tests, as they can trust that the test results will be broadly relevant and beneficial in making well-informed selection and assessment choices (Whetzel & McDaniel, 2009).

By acknowledging the concept of validity generalisation, organisations can streamline their hiring process and increase the likelihood of selecting candidates who will excel in their respective roles (Salgado et al., 2015).  This improves overall productivity and creates a more efficient and successful workforce (Schmidt & Hunter, 1998).


  • Salgado, J.F., Anderson, N., & Tauriz, G. (2015). The validity of ipsative and quasi-ipsative forced-choice personality inventories for different occupational groups: A comprehensive meta-analysis. Journal of Occupational and Organisational Psychology, 88(4), 797-834. https://doi.org/10.1111/joop.12098
  • Schmidt, F.L., & Hunter, J.E. (1998). The validity and utility of selection methods in personnel psychology: Practical and theoretical implications of 85 years of research findings. Psychological Bulletin, 124(2), 262-274. https://doi.org/10.1037/0033-2909.124.2.262
  • Whetzel, D.L., & McDaniel, M.A. (2009). Situational judgement tests: An overview of current research. Human Resource Management Review, 19(3), 188-202. https://doi.org/10.1016/j.hrmr.2009.03.007

Q2.  Define and discuss the concept of differential validity.

Differential validity is a significant concept in psychometrics and human resource management, particularly within selection and assessment processes.  This concept refers to the variation in the predictive validity of a test or assessment method among different subgroups within a population (Berry et al., 2011).  In simpler terms, differential validity occurs when a test or assessment tool accurately forecasts the performance or outcomes for one group but not for another (Ployhart & Holtz, 2008).

The importance of differential validity lies in its potential to reveal biases in the development and application of ability tests (Kaplan & Saccuzzo, 2017).  Such biases may lead to unfair outcomes for specific groups of applicants during the selection and assessment process.  For example, if a test demonstrates differential validity, it might accurately predict job performance for men but not for women, or for individuals from specific ethnic backgrounds but not for others (Hough et al., 2001).  Consequently, this could result in unfair advantages or disadvantages for these subgroups.

Organisations should thoroughly review and analyse their assessment methods to mitigate the effects of differential validity, ensuring fairness and accuracy for all groups (DeNisi & Murphy, 2017).  This process may entail conducting statistical analyses to identify any discrepancies in predictive validity and examining the reasons behind these discrepancies.  If differential validity is discovered, organisations may need to adjust their assessment methods or develop new ones to guarantee a fair and unbiased selection process.


  • Berry, C.M., Clark, M.A., & McClure, T.K. (2011). Racial/Ethnic differences in the criterion-related validity of cognitive ability tests: A qualitative and quantitative review. Journal of Applied Psychology, 96(5), 881-906. https://doi.org/10.1037/a0023222
  • DeNisi, A.S., & Murphy, K.R. (2017). Performance appraisal and performance management: 100 years of progress? Journal of Applied Psychology, 102(3), 421-433. https://doi.org/10.1037/apl0000085
  • Hough, L.M., Oswald, F.L., & Ployhart, R.E. (2001). Determinants, detection and amelioration of adverse impact in personnel selection procedures: Issues, evidence and lessons learned. International Journal of Selection and Assessment, 9(1-2), 152-194. https://doi.org/10.1111/1468-2389.00171
  • Kaplan, R.M., & Saccuzzo, D.P. (2017). Test bias. In Psychological Testing: Principles, Applications, and Issues (9th ed., pp. 520-545). Wadsworth Publishing.
  • Ployhart, R.E., & Holtz, B.C. (2008). The diversity-validity dilemma: Strategies for reducing racioethnic and sex subgroup differences and adverse impact in selection. Personnel Psychology, 61(1), 153-172. https://doi.org/10.1111/j.1744-6570.2008.00109.x
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