RESEARCH METHODS AND
QUANTITATIVE TECHNIQUES
Samenvatting hoorcolleges 2025-2026
Buyse Maité [student]
Vrije Universiteit Brussel
,INHOUDSOPGAVE
1 Psychology is a way of thinking.................................................................................................... 9
Producing versus consuming research............................................................................................... 9
Waarom kritisch denken nodig is ................................................................................................... 9
Hoe wetenschappers werken .......................................................................................................... 10
Empirisme .................................................................................................................................. 10
Scientists test theories:............................................................................................................... 10
Fundamental vs aplied research Fundamenteel vs. toegepast onderzoek ...................................... 13
Continuously envolving: Wetenschap evolueert voortdurend ........................................................ 14
Publishing: Publiceren in de wetenschap ..................................................................................... 14
Communicatie via media ............................................................................................................ 15
2. SOURCES OF INFORMATION .................................................................................................... 16
Waarom onderzoek beter is dan ervaring ......................................................................................... 16
Reasearch vs experience: ............................................................................................................... 16
Voorbeeld: rage rooms ............................................................................................................... 16
Voorbeeld: borstoperaties ........................................................................................................... 16
Onderzoek versus intuïtie ................................................................................................................ 16
Cognitieve biases ....................................................................................................................... 18
Authority figures: Autoriteitsargumenten .......................................................................................... 18
Wetenschappelijke bronnen ......................................................................................................... 18
Overview .................................................................................................................................... 19
1. THREE CLAIMS, FOUR VALIDITIES ............................................................................................. 20
VARIABLES: Wat is een variabele? ................................................................................................... 20
Variabelen vs. constanten ........................................................................................................... 21
Onafhankelijke vs. afhankelijke variabelen ................................................................................... 21
Gemeten vs. gemanipuleerde variabelen ..................................................................................... 21
Conceptuele vs. operationele variabelen ..................................................................................... 21
Voorbeeldonderzoek: sms’en tijdens het rijden ................................................................................ 22
THREE CLAIMS .............................................................................................................................. 23
1. Frequency claims .................................................................................................................... 23
2. Association claims .................................................................................................................. 23
3. Causal claims ......................................................................................................................... 24
THE FOUR BIG VALIDITIES ............................................................................................................. 24
1. Construct validity .................................................................................................................... 24
2. External validity ....................................................................................................................... 24
3. Statistical validity .................................................................................................................... 25
4. Internal validity ....................................................................................................................... 25
VALIDITEIT PER CLAIMTYPE ........................................................................................................... 25
Frequency claims ....................................................................................................................... 25
Association claims...................................................................................................................... 25
Causal claims............................................................................................................................. 26
CONDITIONS FOR CAUSALITY ....................................................................................................... 26
belangrijk: Random assignment ≠ random selection ..................................................................... 26
Voorbeeld: muzieklessen verhogen IQ (Schellenberg, 2004) ......................................................... 27
SPURIOUS ASSOCIATIONS ............................................................................................................ 27
[Typ hier] [Typ hier] [Typ hier] 1
, CORRELATION ≠ CAUSATION ........................................................................................................ 27
PRIORITIZING VALIDITY ................................................................................................................. 27
2. ETHICAL GUIDELINES FOR PSYCHOLOGY RESEARCH ............................................................... 28
HISTORISCHE VOORBEELDEN ..................................................................................................... 28
1. Historical example: Tuskegee Syphilis Study (1932–1972) ............................................................. 28
2. historical example: Milgram’s obedience experiment .................................................................... 28
3. historical example: Invasion of personal space (urinal study)......................................................... 29
THE BELMONT REPORT.................................................................................................................. 29
Drie basisprincipes ..................................................................................................................... 29
APA GUIDELINES ........................................................................................................................... 29
Vijf algemene principes ............................................................................................................... 29
APA Guidelines - Standard 8 ........................................................................................................ 30
RESEARCH FRAUD ........................................................................................................................ 31
Vormen ...................................................................................................................................... 31
Prevalentie (Fanelli, 2009) ........................................................................................................... 31
QUESTIONABLE RESEARCH PRACTICES (QRPs) ............................................................................ 32
Anderson and colleagues (2013): ................................................................................................. 32
OPEN SCIENCE ............................................................................................................................. 32
ANIMAL RESEARCH ....................................................................................................................... 33
Identifying Good Measurement & Surveys/Observations .......................................................... 34
1. Identifying Good Measurement ................................................................................................ 34
Different ways to measure a variable ............................................................................................... 34
Construct validity & reliability...................................................................................................... 34
Overzicht........................................................................................................................................ 34
Reliability ....................................................................................................................................... 35
Test-retest reliability ................................................................................................................... 35
Interrater reliability ..................................................................................................................... 35
Internal consistency reliability ..................................................................................................... 36
Construct validity............................................................................................................................ 37
Construct validity: subjectieve vormen ........................................................................................ 37
Construct validity: empirische vormen ......................................................................................... 37
Evaluating reliability and construct validity in articles Voorbeeld: Gordon et al. (2012) – AIR Scale ....... 38
2. Surveys and Observations........................................................................................................ 39
Vormen van surveys ........................................................................................................................ 39
ESM= Experience Sampling Method .......................................................................................... 39
Single- vs. multi-item measures....................................................................................................... 40
Schalen ontwikkelen ....................................................................................................................... 40
Choosing the question format ..................................................................................................... 40
Writing well-worded questions: Goed geformuleerde vragen......................................................... 42
Encouraging accurate answers / Accurate antwoorden stimuleren ............................................... 42
Detectie van lage datakwaliteit (Desimone & Harms, 2017)........................................................... 43
Observaties ................................................................................................................................... 44
Voorbeeld: praten vrouwen meer dan mannen? ........................................................................... 44
[Typ hier] [Typ hier] [Typ hier] 2
, Problemen bij observaties ........................................................................................................... 44
Oplossingen ............................................................................................................................... 44
Sampling (Chapter 7) ................................................................................................................... 45
Wat is een steekproef? .................................................................................................................... 45
Some key terms / Basic Concepts ................................................................................................... 45
Population-of-interest ................................................................................................................. 45
Census....................................................................................................................................... 45
Sampling frame .......................................................................................................................... 45
Sample....................................................................................................................................... 45
Representative vs non-representative sample .............................................................................. 45
Probability vs biased sampling .................................................................................................... 45
Key Issue: Generalizability ............................................................................................................... 46
External validity .......................................................................................................................... 46
Belangrijk inzicht ........................................................................................................................ 46
Illustration: Problemen bij generaliseren .......................................................................................... 46
Sampling Bias................................................................................................................................. 47
Sampling error ............................................................................................................................ 47
Unbiased sample ........................................................................................................................ 47
Biased sample ............................................................................................................................ 47
Ways sample may be biased ....................................................................................................... 47
Sampling Techniques ...................................................................................................................... 48
Biased vs unbiased techniques ................................................................................................... 48
Unbiased sampling ..................................................................................................................... 49
Simple Random Sample .................................................................................................................. 49
Cluster Sampling ............................................................................................................................ 49
Stratified Random Sample............................................................................................................... 50
Oversampling ................................................................................................................................. 50
Raking Example .......................................................................................................................... 51
Systematic Sampling ...................................................................................................................... 52
Multistage Sampling ....................................................................................................................... 52
Biased Sampling (non-probability) ............................................................................................... 53
Convenience Sample ...................................................................................................................... 53
Purposive Sampling ........................................................................................................................ 53
Snowball Sampling ......................................................................................................................... 53
Quota Sampling .............................................................................................................................. 54
Illustration & exercise ................................................................................................................. 55
15 Illustration: Literary Digest (1936) ............................................................................................... 55
Exercise (VUB Library Sampling) ...................................................................................................... 55
Sampling .................................................................................................................................... 56
When Is External Validity Important? ................................................................................................ 56
18. How to Evaluate External Validity ............................................................................................... 56
19. WEIRD Samples ........................................................................................................................ 56
[Typ hier] [Typ hier] [Typ hier] 3
QUANTITATIVE TECHNIQUES
Samenvatting hoorcolleges 2025-2026
Buyse Maité [student]
Vrije Universiteit Brussel
,INHOUDSOPGAVE
1 Psychology is a way of thinking.................................................................................................... 9
Producing versus consuming research............................................................................................... 9
Waarom kritisch denken nodig is ................................................................................................... 9
Hoe wetenschappers werken .......................................................................................................... 10
Empirisme .................................................................................................................................. 10
Scientists test theories:............................................................................................................... 10
Fundamental vs aplied research Fundamenteel vs. toegepast onderzoek ...................................... 13
Continuously envolving: Wetenschap evolueert voortdurend ........................................................ 14
Publishing: Publiceren in de wetenschap ..................................................................................... 14
Communicatie via media ............................................................................................................ 15
2. SOURCES OF INFORMATION .................................................................................................... 16
Waarom onderzoek beter is dan ervaring ......................................................................................... 16
Reasearch vs experience: ............................................................................................................... 16
Voorbeeld: rage rooms ............................................................................................................... 16
Voorbeeld: borstoperaties ........................................................................................................... 16
Onderzoek versus intuïtie ................................................................................................................ 16
Cognitieve biases ....................................................................................................................... 18
Authority figures: Autoriteitsargumenten .......................................................................................... 18
Wetenschappelijke bronnen ......................................................................................................... 18
Overview .................................................................................................................................... 19
1. THREE CLAIMS, FOUR VALIDITIES ............................................................................................. 20
VARIABLES: Wat is een variabele? ................................................................................................... 20
Variabelen vs. constanten ........................................................................................................... 21
Onafhankelijke vs. afhankelijke variabelen ................................................................................... 21
Gemeten vs. gemanipuleerde variabelen ..................................................................................... 21
Conceptuele vs. operationele variabelen ..................................................................................... 21
Voorbeeldonderzoek: sms’en tijdens het rijden ................................................................................ 22
THREE CLAIMS .............................................................................................................................. 23
1. Frequency claims .................................................................................................................... 23
2. Association claims .................................................................................................................. 23
3. Causal claims ......................................................................................................................... 24
THE FOUR BIG VALIDITIES ............................................................................................................. 24
1. Construct validity .................................................................................................................... 24
2. External validity ....................................................................................................................... 24
3. Statistical validity .................................................................................................................... 25
4. Internal validity ....................................................................................................................... 25
VALIDITEIT PER CLAIMTYPE ........................................................................................................... 25
Frequency claims ....................................................................................................................... 25
Association claims...................................................................................................................... 25
Causal claims............................................................................................................................. 26
CONDITIONS FOR CAUSALITY ....................................................................................................... 26
belangrijk: Random assignment ≠ random selection ..................................................................... 26
Voorbeeld: muzieklessen verhogen IQ (Schellenberg, 2004) ......................................................... 27
SPURIOUS ASSOCIATIONS ............................................................................................................ 27
[Typ hier] [Typ hier] [Typ hier] 1
, CORRELATION ≠ CAUSATION ........................................................................................................ 27
PRIORITIZING VALIDITY ................................................................................................................. 27
2. ETHICAL GUIDELINES FOR PSYCHOLOGY RESEARCH ............................................................... 28
HISTORISCHE VOORBEELDEN ..................................................................................................... 28
1. Historical example: Tuskegee Syphilis Study (1932–1972) ............................................................. 28
2. historical example: Milgram’s obedience experiment .................................................................... 28
3. historical example: Invasion of personal space (urinal study)......................................................... 29
THE BELMONT REPORT.................................................................................................................. 29
Drie basisprincipes ..................................................................................................................... 29
APA GUIDELINES ........................................................................................................................... 29
Vijf algemene principes ............................................................................................................... 29
APA Guidelines - Standard 8 ........................................................................................................ 30
RESEARCH FRAUD ........................................................................................................................ 31
Vormen ...................................................................................................................................... 31
Prevalentie (Fanelli, 2009) ........................................................................................................... 31
QUESTIONABLE RESEARCH PRACTICES (QRPs) ............................................................................ 32
Anderson and colleagues (2013): ................................................................................................. 32
OPEN SCIENCE ............................................................................................................................. 32
ANIMAL RESEARCH ....................................................................................................................... 33
Identifying Good Measurement & Surveys/Observations .......................................................... 34
1. Identifying Good Measurement ................................................................................................ 34
Different ways to measure a variable ............................................................................................... 34
Construct validity & reliability...................................................................................................... 34
Overzicht........................................................................................................................................ 34
Reliability ....................................................................................................................................... 35
Test-retest reliability ................................................................................................................... 35
Interrater reliability ..................................................................................................................... 35
Internal consistency reliability ..................................................................................................... 36
Construct validity............................................................................................................................ 37
Construct validity: subjectieve vormen ........................................................................................ 37
Construct validity: empirische vormen ......................................................................................... 37
Evaluating reliability and construct validity in articles Voorbeeld: Gordon et al. (2012) – AIR Scale ....... 38
2. Surveys and Observations........................................................................................................ 39
Vormen van surveys ........................................................................................................................ 39
ESM= Experience Sampling Method .......................................................................................... 39
Single- vs. multi-item measures....................................................................................................... 40
Schalen ontwikkelen ....................................................................................................................... 40
Choosing the question format ..................................................................................................... 40
Writing well-worded questions: Goed geformuleerde vragen......................................................... 42
Encouraging accurate answers / Accurate antwoorden stimuleren ............................................... 42
Detectie van lage datakwaliteit (Desimone & Harms, 2017)........................................................... 43
Observaties ................................................................................................................................... 44
Voorbeeld: praten vrouwen meer dan mannen? ........................................................................... 44
[Typ hier] [Typ hier] [Typ hier] 2
, Problemen bij observaties ........................................................................................................... 44
Oplossingen ............................................................................................................................... 44
Sampling (Chapter 7) ................................................................................................................... 45
Wat is een steekproef? .................................................................................................................... 45
Some key terms / Basic Concepts ................................................................................................... 45
Population-of-interest ................................................................................................................. 45
Census....................................................................................................................................... 45
Sampling frame .......................................................................................................................... 45
Sample....................................................................................................................................... 45
Representative vs non-representative sample .............................................................................. 45
Probability vs biased sampling .................................................................................................... 45
Key Issue: Generalizability ............................................................................................................... 46
External validity .......................................................................................................................... 46
Belangrijk inzicht ........................................................................................................................ 46
Illustration: Problemen bij generaliseren .......................................................................................... 46
Sampling Bias................................................................................................................................. 47
Sampling error ............................................................................................................................ 47
Unbiased sample ........................................................................................................................ 47
Biased sample ............................................................................................................................ 47
Ways sample may be biased ....................................................................................................... 47
Sampling Techniques ...................................................................................................................... 48
Biased vs unbiased techniques ................................................................................................... 48
Unbiased sampling ..................................................................................................................... 49
Simple Random Sample .................................................................................................................. 49
Cluster Sampling ............................................................................................................................ 49
Stratified Random Sample............................................................................................................... 50
Oversampling ................................................................................................................................. 50
Raking Example .......................................................................................................................... 51
Systematic Sampling ...................................................................................................................... 52
Multistage Sampling ....................................................................................................................... 52
Biased Sampling (non-probability) ............................................................................................... 53
Convenience Sample ...................................................................................................................... 53
Purposive Sampling ........................................................................................................................ 53
Snowball Sampling ......................................................................................................................... 53
Quota Sampling .............................................................................................................................. 54
Illustration & exercise ................................................................................................................. 55
15 Illustration: Literary Digest (1936) ............................................................................................... 55
Exercise (VUB Library Sampling) ...................................................................................................... 55
Sampling .................................................................................................................................... 56
When Is External Validity Important? ................................................................................................ 56
18. How to Evaluate External Validity ............................................................................................... 56
19. WEIRD Samples ........................................................................................................................ 56
[Typ hier] [Typ hier] [Typ hier] 3
