MGTO 231 Human Resources Management Personnel selection I Dr. Kin Fai Ellick WONG

Questions for you The objective of selection is very simple: –Choosing the “correct” person However, we do not have magic, there are often many “incorrect choices” in our decisions A more realistic objective for selection seems to be: –Minimizing the probability of making an incorrect selection –How? I hope you will get some insights at the end of this class

Outline In Personnel selection I –The basic concepts –Measurement errors –Reliability In Personnel selection II –Validity –Selection tools Letter of recommendation, ability tests, personality tests, interviews, handwriting analysis, etc.

Outline Selection I Basic Concepts Measurement errors Reliability

Selection as prediction I want to have employees with good performance I cannot know their performance before hiring I can just predict from applicants’ various characteristics Some individuals are more likely to have better performance than others (remember the idea of individual differences)

What are the predictors Any characteristics associated with individual differences –Age, gender, IQ, EQ, interpersonal skills, education level, openness, extroversion, academic performance, etc. –Some may be better predictors than others (more reliable and valid)

All selection methods are to measure these characteristics and the associations between these characteristics with different aspects of performance Selection  individual characteristics  performance Tools  predictors  performance

Two major issues in selection –How consistent is the prediction (reliability) –How well is the prediction (validity) Is it really measuring what it is supposed to measure?

An example of a good and a bad predictor Y Academic Results Job Performance Y Interview’s rating Job Performance Which one has positive relationship with job performance?

Outline Selection I Basic Concepts Measurement errors Reliability

Measurement errors Please answer questions 1 and 2

Measurement errors Error is not equal to mistake Error is a kind of inaccuracy and variability Error can be reduced if the measuring device is precise, but it cannot be completely eliminated

Observed score = –True score + systematic errors + random errors Systematic errors –A constant is added to every measure –Observed score = True score + constant Random errors –A random value is added to every measure –The random values are normally distributed, with mean = 0 –Observed score = True score + random value

Sources of errors Systematic errors –Basic characteristics of the measuring device Random errors –Physical Temperature, humanity, loudness, brightness, etc. –Psychological Fatigue, motivation, adaptation to new environments –Sampling error domain sampling model

Outline Selection I Basic Concepts Measurement errors Reliability

Reliability ( 可靠度 ) Definition –(Textbook) The consistency of scores obtained by the same person when retested with the identical or equivalent tests

Measurement errors and reliability Which kind of errors, systematic or random, may affect the reliability of a measurement?

The purpose of testing –Assessing individual difference –The influence of systematic errors on this purpose is, everyone’s score is biased by a constant. The relative performance is unchanged Low T always gets low X, and high T always gets high X –The influence of random errors: Low T may obtain high X, and high T may obtain low X The probability of Low T getting high X increases as random error increases

What is a reliable measurement? A test that can truly reflect the “True score” is claimed as a reliable test For a perfectly reliable test –The correlation between the true score (T) and the observed score (X) is 1 –X can be fully accounted by T For a perfectly unreliable test –The correlation between T and X is 0 –T accounts for nothing about X

Tests that are relatively free of measurement (random) errors are deemed to be reliable There is much less concern with systematic errors The term “errors” usually refers to random errors

Which one is more reliable? –Tests that are relatively free of measurement random errors are deemed to be reliable –Reliability refers to consistency of measurement or repeatability TrialThermometer AThermometer BThermometer C

Methods measuring reliability Test-retest Parallel/alternate forms Split half Alpha (internal consistency)

How do you interpret this picture? –Please tell me a story about the picture Is this test reliable? –Why?

Conclusion I’ve asked: –A more realistic objective for selection seems to be: Minimizing the probability of making an incorrect selection How? Step 1:Using test with high reliability –Checking the reliability before and after using I’ll discuss the other step about “validity” in next lesson