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Developing a Hiring System. Reliability of Measurement. Key Measurement Issues. Measurement is imperfect Reliability --how accurately do our measurements reflect the underlying attributes? Validity --how accurate are the inferences we draw from our measurements?
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Developing a Hiring System Reliability of Measurement
Key Measurement Issues • Measurement is imperfect • Reliability--how accurately do our measurements reflect the underlying attributes? • Validity --how accurate are the inferences we draw from our measurements? • refers to the uses we make of the measurements
What is Reliability? • The extent to which a measure is free of measurement error • Obtained score = • True Score + • Random Error + • Constant Error
What is Reliability? Reliability coefficient = % of obtained score due to true score • e.g., Performance measure with ryy = .60 is 60% “accurate” in measuring differences in true performance Different “types” of reliability reflect different sources of measurement error
Types of Reliability • Test-retest Reliability • Assesses stability (over time/situations) • Internal Consistency Reliability • Assesses consistency of content of measure • Parallel Forms Reliability • Assesses equivalence of measures • Inter-rater reliability is special case
Developing a Hiring System Validity of Measurement
What is Validity? The accuracy of inferences drawn from scores on a measure • Example: An employer uses an honesty test to hire employees. • The inference is that high scorers will be less likely to steal. • Validation confirms this inference.
Validity vs. Reliability • Reliability is a characteristic of the measure • Error in measurement • A measure either is or isn’t reliable • Validity refers to the uses of the measures • Error in inferences drawn • May be valid for one purpose but not for another
Validity and Job Relatedness • Federal regulations require employer to document job-relatedness of selection procedures that have adverse impact • Good practice also dictates that selection decisions should be job-related • Validation is the typical way of documenting job relatedness
Methods of Validation • Empirical: showing a statistical relationship between predictor scores and criterion scores • showing that high-scoring applicants are better employees • Content: showing a logical relationship between predictor content and job content • showing that the predictor measures the same knowledge or skills that are required on the job
Methods of Validation • Construct: developing a “theory” of why a predictor is job-relevant • Validity Generalization: “Borrowing” the the results of empirical validation studies done on the same job in other organizations
Empirical Validation • Concurrent Criterion-Related Validation • Predictive Criterion-Related Validation
Concurrent Validation Design Time Period 1 Test current employees Measure employee performance Validity?
Predictive Validation Design Time Period 1 Time Period 2 Hire applicants Test applicants Obtain criterion measures Validity?
Content Validation • Inference being tested is that the predictor samples actual job skills and knowledge • not that predictor scores predict job performance • Avoids the problems of empirical validation because no statistical relationship is tested • potentially useful for smaller employers
Construct Validation Making a persuasive argument that hiring tool is job-relevant 1. Why attribute is necessary • job & organizational analysis 2. Tool measures the attribute • existing data usually provided by developer of tool
Construct Validation Example Validating FOCUS as measure of attention to detail (AD) for QC inspectors • Develop rationale for importance of AD • Defend FOCUS as measure of AD • Comparison of FOCUS scores with other AD tests • Comparison of FOCUS and related tests • Comparison of scores for people in jobs requiring high or low levels of AD • Evidence of validity in similar jobs
Construct Validation Example Validating an integrity (honesty) test • Develop rationale for importance of honesty • Defend test as measure of honesty • Comparison of test scores with other honesty measures • Reference checks, polygraphs, other honesty tests • Comparison of test scores with related tests • Comparison of scores for “honest” and “dishonest” people • Evidence of validity in similar jobs
Validity Generalization • Logic: A test that is valid in one situation should be valid in equivalent situations • Fact: Validities differ across situations • Why?
Validity Generalization Two possible explanations whyvalidities differ across situations: • Situations require different attributes vs. • “Statistical artifacts”; differences in: • Sample sizes • Reliability of predictor and criterion measures • Criterion contamination/deficiency • Restriction of range
VG Implications • Validities are larger and more consistent • Validities are generalizable to comparable situations • Tests that are valid for majority are usually valid for minority groups • There is at least one valid test for all jobs • It’s hard to show validity with small Ns
Validation: Summary • Criterion-Related • Predictive • Concurrent • Content • Construct • Validity Generalization • “Face Validity”