Reliability & Validity

Question 1

Define internal reliability and how it is reduced

Answer 1

The extent to which a measure is consistent within itself
- usually issues in procedure: operationalisation of variables, order effects (repeated measures design), lack of standardisation of procedures, accuracy of measuring tool

Question 2

How is counterbalancing used to reduce effect of order effects?

Answer 2

• population is split to 2 halves where one half do step 2 then 1, and the other do step 1 then 2

Question 3

Explain standardisation

Answer 3

• process of ensuring the experience of the research is identical for all Ps
• provide a standard set of instructions using same environment to control as many variables as possible
• allows data collection to establish a cause and effect
  —> utilise scientific measuring tools where possible so data is easy to compare

Question 4

Explain external reliability and what can reduce it

Answer 4

• the extent to which a test produces consistent results over several occasions with the same Ps
• issues commonly relate to the consistency of results over time and across different populations
  —> location can be a problem as acts as a barrier to external reliability. Only solution is to conduct research in controlled conditions (ie lab) but this reduces validity

Question 5

Experimental way to show internal reliability

Answer 5

Split half: split Ps into 2 or more groups and test conditions one at a time
—> if tests show similar results it can be argued it has internal reliability

Question 6

Experimental way to show external reliability

Answer 6

Test re-test: same Ps tested over a period of time or separate occasions using same procedures
—> if results similar then external reliability

Question 7

Explain inter-rater reliability

Answer 7

Where two or more psychologists produce consistent results by using a standardised procedure, an agreed coding system or a correlation of their data
—> prevents variation of data collected by multiple psychologists / researchers

Question 8

What is validity?

Answer 8

• reasonably certain that findings of study reflect real life behaviour

Question 9

External validity

Answer 9

• whether the study paints a true picture of real life behaviours and whether findings would be applicable to other places, times and people
• population validity, ecological validity, historical validity

Question 10

Internal validity

Answer 10

• the study measures what it intends to measure as confounding variables have been controlled and will not affect results
• accurate and effects on DV caused by IV

Question 11

What can cause validity issues?

Answer 11

Extraneous variables

Question 12

How to prevent participant variables influencing validity

Answer 12

• use a matched pairs design
• assign Ps randomly so chance of individual differences is lower

Question 13

How to prevent situational variables affecting validity

Answer 13

• keep all aspects the same for all Ps
• counterbalancing to reduce order effects

Question 14

How to prevent experimenter variables impacting validity

Answer 14

• experimenter act in neutral manner
• standardised instruction set for Ps
• double blind study
• pilot study

Question 15

How to prevent participant effects impacting validity

Answer 15

• field experiment
• anonymous Ps
• single blind study

Question 16

How to prevent stimuli variables influencing validity

Answer 16

• independent measures
• repeated measures designed to