PSYC232 Week 2

Ceiling Effects

Occurs when responses are clustered at the high end of a scale, making it difficult to distinguish among high scorers.

Floor Effects

Occurs when responses are clustered at the low end of a scale, making it hard to differentiate among low scorers.

Acquiescence Bias

The tendency for respondents to agree with statements more than they disagree, which can skew survey results.

Cronbach’s Alpha

A measure of internal consistency for a set of scale or test items, indicating how closely related a set of items are.

Priming

The influence of previously experienced stimuli on responses to subsequent questions, potentially altering participants' interpretation.

Principal Components Analysis (PCA)

A statistical method used to reduce the dimensionality of data by identifying patterns and grouping related questions.

Demand Characteristics

Situational cues that influence participants' behavior to align with what they perceive the researcher expects.

Social Desirability Bias

The tendency of respondents to answer questions in a manner that will be viewed favorably by others.

Scree Plot

A graphical representation used in PCA to determine the number of components to retain by showing the variance explained by each component.

Double-Blind Measures

Methodology where both the participants and researchers are unaware of the key aspects of the study to avoid bias.

Factor Analysis

A statistical method used to identify underlying relationships between variables in a dataset.

Construct Validity

The extent to which a test measures the concept it is intended to measure.

Reliability

The degree to which a measure produces stable and consistent results over time.

Validity

The accuracy of a measure in assessing what it is supposed to measure.

Item loadings

A number that goes from -1 to 1

6 steps to report the PCA

1. Examine the table of loadings from the PCA

2. COnsider re-starting if items cross-load  or do not load.

3. Convert to an APA table with item labels

4. Identify the common theme of the components

5. Average together the items to form a scale (remember to reverse-code items that have negative loadings)

6. Report the descriptive statistics/reliability for your new scale.

Components

Looks at people's responses to the items and groups them to make the best summary of the items.