Research method & design in I-O Psychology Lecture 2 (Jan 28, 2002) Major ref: Riggio, Ch 2 (w/o appendix); Supplementary reading: Spector, Ch 2 (p )

2002/1/28 2 Outline l Social scientific research methods k goals and steps l Major research designs k experimental and correlational designs l Measurement of variables k observational k self-report

2002/1/28 3 Social scientific research methods l I/O psychology is the science of human behavior at work l Involves systematic way to examine an issue (Scientific methods) k e.g., Does the employee re-training program improve employability? l Intuition, experience -> subjectivity

2002/1/28 4 Steps in the research process l 1- Formulation of the problem or issue k identify an area of interest k identify a focus u E.g., Employee re-training program …. u Improve employability? u Used the most effective teaching method? u Is the effect long lasting?

2002/1/28 5 Steps in the research process l 2 - Generation of hypotheses k get the basics u literature search; preliminary observations, experience; interviews k Further narrow the focus to one statement - hypothesis - the supposed relationships among variables k An example:

2002/1/28 6 The re-training program improves people’s employability Generating a hypothesis

2002/1/28 7 l 3 - Selecting the research design k guide the actual collection of data k research settings u laboratory vs. field k two major designs u Experimental or correlational u others: case study; meta-analysis Steps in the research process

2002/1/28 8 l 3 - Selecting the research design k How to select the design? u Experimental - u E.g., whether someone undergoes the re- training program u Correlational - u E.g., age, IQ, no. of siblings, nationality

2002/1/28 9 l 4 - Collection of data k sampling u who is qualified to be participants? u where to locate the participants? u random selection - equal chance of being selected –e.g., u may affect the generalizability of the results Steps in the research process

2002/1/28 10 l 5 & 6 - data analysis and results interpretation k use appropriate statistical analyses k mean, SD, correlation, regression, analysis of variance Steps in the research process

2002/1/28 11 Research designs l Experimental design l Independent variable (IV) k examines its effects on people u e.g., re-training program; salary increase; k manipulated (varied) by the researcher u e.g., absence/presence; amount; frequency

2002/1/28 12 Experimental design l Dependent variable (DV) k the part of the person that is being affected u employability; work performance; absenteeism; weight loss; English proficiency k measured by the researcher u reveal the effects of the IV l change in DV is presumed to be caused by the change in IV

2002/1/28 13 Exercise l I think having a big meal before class makes people sleepy. l The more books you read, the faster you can read. l Will employees become more motivated if you threaten them? l You will put on weight if you have food within 3 hours before you sleep. l Comparing to youngster who do not receive monetary incentive, those who do are more likely to complete the spring board program. l I think no matter if you complete the spring board program or not, you will be offered similar number of jobs.

2002/1/28 14 Experimental design l Case: k Ho: The probability of getting a job is higher for people who have taken the re- training program than those who have not. k IV: k DV: k Sample:

2002/1/28 15 Experimental design Treatment gp Control gp Sample Measure the DV Measure the DV Re-training program No training Compare the difference Implement the IV

2002/1/28 16 Experimental design Treatment gp Control gp Assign people to treatment and control groups  what if assignment is non- random? By application? Sample

2002/1/28 17 Experimental design Treatment gp Control gp Random Assignment Random assignment  Assign people into treatment or ctl gp randomly  Equal chance of being assigned to either gp  Aims at

2002/1/28 18 Treatment gp Control gp Measure the DV Measure the DV Re-training program No training Implement the IV The 2 groups are equivalent The 2 groups begin to differ Random Assignment

2002/1/28 19 Experimental design Treatment gp Control gp Random Assignment Measure the DV Measure the DV Re-training program No training Compare the difference Implement the IV

2002/1/28 20 Experimental design l The difference in DV between the treatment and ctl gp = effects of IV (the treatment/manipulation) l Strength k l Weakness k

2002/1/28 21 Correlational design l All variables are measured as they naturally occur l No manipulation by researcher k No treatment or control group k No random assignment l Examples : k Effects of personality, weather, no. of sibling on… k employability, absenteeism, English proficiency

2002/1/28 22 Correlational design l Correlation between the two variables k Positive or Negative? u Self-esteem - life satisfaction u Job satisfaction - quit intention u Senior year students - absenteeism u Length of queue - waiting time for the next bus u Birth order - extraversion

2002/1/28 23 Correlational design l Strength k k l Weakness k k illustration: love reading comic - language proficiency (-ve relationship) l How to select the design? (s.8)

2002/1/28 24 Measurement of variable l Observational k Obtrusive - individuals know that they are being assessed u E.g., assessment centre u E.g., u Weakness - k Unobtrusive - aware of the observer, but do not know that they are being studied u E.g., one-way mirror, using video tape u E.g.,

2002/1/28 25 Measurement of variable l Self-report k obtain information from participants’own report, very popular u survey (paper-n-pencil, telephone, face-to-face) u time and cost efficient, require less manpower k Weakness u biased; memory error; concern for face, only give socially accepted answers, etc..