---
title: Factor analysis
description: "| Factor Analyses (FA) are a set of techniques that allows us to look in more detail at the strength of underlying correlations between scores on the items of a measure. These provide some useful indication about whether items appear…"
url: "https://www.psyctc.org/psyctc/glossary2/factor-analysis/"
updated: "2026-03-06"
category: All OM book glossary entries
---

# Factor analysis

| Factor Analyses (FA) are a set of techniques that allows us to look in more detail at the strength of underlying correlations between scores on the items of a measure. These provide some useful indication about whether items appear to tap common, i.e. shared, sources of variation between individuals, a major part of **construct validity**. Historically FA was exploratory: **Exploratory Factor Analysis (EFA)**. (In reality, a closely related approach called **Principal Component Analysis (PCA)** was often used and reported as an EFA though it's actually a distinct method.) Less often, **Multi-Dimensional Scaling (MDS)** has been used for similar purposes: it analyses ordinal correlations rather than correlations using the raw item scores. More recently, with much more computer power available, **Confirmatory Factor Analysis (CFA)**, which can test an expected mapping of items to presumed factors has become fashionable and has almost displaced EFA, PCA and MDS. |
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#### Detail

See **Confirmatory Factor Analysis (CFA)** and **Exploratory Factor Analysis (EFA)** for more detail, **Construct Validity** for background detail. **Principal Component Analysis (PCA)** and **Multi-Dimensional Scaling (MDS)** are background, not central to FA.

#### Try also ...

[Bifactor analysis](https://www.psyctc.org/psyctc/glossary2/bifactor-models/)
[Confirmatory Factor Analysis (CFA)](https://www.psyctc.org/psyctc/glossary2/confirmatory-factor-analysis/)
Construct Validity
[Exploratory Factor Analysis (EFA)](https://www.psyctc.org/psyctc/glossary2/exploratory-factor-analysis-efa/)
[Multi-Dimensional Scaling (MDS)](https://www.psyctc.org/psyctc/glossary2/multidimensional-scaling-mds/)
[Principal Component Analysis (PCA)](https://www.psyctc.org/psyctc/glossary2/principal-component-analysis-pca/)

#### Chapters

Not developed in the OMbook.

#### Further reading

Should be developed in [the Rblog](https://www.psyctc.org/Rblog/index.html) but not there yet.

#### Online applications

Nothing likely.

#### Dates

Started before 14.xi.21, last tweaked 6.iii.26.