mgto 231 human resources management personnel selection i dr. kin fai ellick wong
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MGTO 231Human 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
Trial Thermometer A Thermometer B Thermometer C
1 101 103 108
2 99 97 108
3 100 102 107
4 101 103 108
5 99 95 108
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