Factor Analysis

Question 1

What is a factor analysis?

Answer 1

• Identify psychological constructs from a scale
  Are they driven by the same underlying factor?
• Reduce the number of variables in a data set
  Representations of themes or constructs

Question 2

What are the different types of factor analysis?

Answer 2

• Principal component analysis (focus)
  New measurement
• Exploratory factor analysis
  Questions that tap into the same factor or factors, ask if they have the same underlying concept
• Confirmatory factor analysis
  Adapting to new context or new language

Question 3

What is needed to do before factor analysis can begin?

Answer 3

• Check correlation
  Needs to be reasonable between items
• Multicollinearity
  If any item is over r=+.90
  -Singularity
  Perfect correlation

Question 4

What tests need to be included in factor analysis?

Answer 4

• Kaiser-Meyer-Olkin
  Compact association, distinct and reliable factor
  Should be .50, pref over .80
  How well suited the items are for factor analysis
• Bartlett’s test of sphericity
  Do we have good correlation among scale items?
  Should be significant= decent correlation

Question 5

Factor Analysis - SPSS output

Answer 5

Table 1
- Correlation between scale items
Table 2
- KMO and Bartlett’s Test
Table 3
- Information about proportion of common variance in a variable
- 0 = has a unique variance
- 1 = share variance with others
- Extraction= to make conclusions, % overlap with overall variation of the other items
Table 4
- Decide how many factors our scale is composed of (extraction)
- Eigenvalue = variation explained by a factor
- Retain all factors greater than 1
Table 5
- Scree plot; how many factors we should retain
- Find point inflextion, drastic change in slope
- Retain factors on the left side of point inflextion
Table 7
- Info of which items makes up a factor
- Conventional cut off for factor loadings .30
Table 8
- Info of correlation between factors

Question 6

Factor Analysis - APA style

Answer 6

• What we performed
• How many items
• How many factors
  Eigenvalues
• Explained variation from factors
• How many items in each factor, their loading range
• Inter-item reliability for each factor
• Conclusion

Question 7

What is item-scale correlations?

Answer 7

How different each scale is to the factor