In pairs, think of how we use the words reliability and validity in everyday life.

What do these words mean? Is there a difference between them or do they mean the same thing?

When assessing the reliability of a study, we generally need to ask two questions1. Can the study be replicated?2. If so, will the results be consistent?

High vs low reliability

Match the method of estimating reliability to the description (pg165)

Test-Retest

reliability

If the measure depends upon interpretation of behaviour, we can compare the results from two or more raters.

If the results in the two halves are similar, we can assume the test is reliable

Split Half

Reliability

Splitting a test into two halves, and comparing the scores in both halves

If the results on the two tests are similar, we can assume the test is reliable

Inter-Rater

reliability

The measure is administered to the same group of people twice

If there is high agreement between the raters, the measure is reliable

ControlDid the IV cause the DV?

Realism Does the experiment reflect real life?Mundane realism

GeneralisabilityCan we generalise our results to the

general population?

Realism vs Control

Internal validityWhat happens inside the study.

External ValidityHow our results can be generalised beyond

the study Validity of psychological measures

How well our methods of measurement actually measure what we intend

Mundane realism Extraneous variables

Situational variablesParticipant variables Investigator effectsDemand characteristicsParticipant effects

Task A and BName the variablesWhat are the EVs and how could they have

been controlled?

Read pg 165-166 and fill in the gaps

Operationalisation of variablesCan result in loss of validity

Content validityDoes the method used actually seem to

measure what you intended? Concurrent validity

How well does the measure agree with existing measures?

Construct validity Is the method actually measuring all parts

of what we are aiming to test? Predictive validity

Is our measure associated with future behaviour?

Complete tacks C, D and E.

Types of Validity

Experimental ValidityValidity of psychological

measures

Internal Validity

External Validity

Extraneous variables

Situational Variables

Participant Variables

Investigator effects

Demand characteristics

Participant effects

Ecological validity

Population validity

Content Validity

Concurrent validity

Mundane realism

Construct validity

Predictive validity