Quantitative data collection

Question 1

Methods

Answer 1

• Physiological measurements
• Observations
• Interviews
• Questionnaires
• Secondary data: records, publication, research

Question 2

Questionnaire + adv/dis

Answer 2

Instrument that involves a set of written questions to gain information
* Adv: cheap, anonymity, large number of people at distances
* Dis: literacy barrier, low response rate, self-selection bias, lack of clarity

Question 3

Secondary data adv/dis

Answer 3

• Adv: data linkage (history through time)
• Dis: reliability and validity, extraction error, incomplete data

Question 4

Design steps

Answer 4

• What informatio is needed
• Define population, sample size
• Budget and timeline
• Survey method (consider wording, length, open/closed questions, leading questions, use of likert)
• Pilot test (assess reliability and validity)
• Distribute and return
• Analyse and communicate

Question 5

How to increase response rate

Answer 5

• Create publicity
• Oversample
• Promote value
• Create incentives
• Make easy
• Do follow ups

Question 6

Observed scored =

Answer 6

OS: true variance + error variance

Error variance: randoms errors (behaviour changes or observer error) and systematic errors (instrument calibration, social desirability)

Question 7

Instrument reliability

Answer 7

Consistency in producing the same result, assessed using correlation coefficient (usually >0.7)

Components
* Stability (same result on repetition): using test-retest (pearsons r)
* Homogeneity (all items measure same concept = internal consistency): using cronbachs alpha
* Equivalence (same result from different observers): using interrelater reliability (kappa coefficient)

Question 8

Instrument validity

Answer 8

Accuracy of the measurement
Assessed using content validity index (expert rating 1-4) and factor analysis (extent to which the items measure the same construct)