Big Five Personality Test: Item & Scale Analysis

Psychometric analysis of the 50-item IPIP Big Five Factor Markers questionnaire in R, including item statistics, factor analysis, and reliability estimation.

Data

This project uses the Big Five Personality Test dataset from Kaggle (~1M responses to the 50-item IPIP Big Five questionnaire).

Setup

1. Install R (>= 4.0) from r-project.org
2. Download the data from Kaggle and place data-final.csv into the src_data/ folder
3. Install packages by running setup.R:

   source("setup.R")

Alternatively, download the data via the Kaggle CLI:

kaggle datasets download -d tunguz/big-five-personality-test -p src_data/ --unzip

Scripts

The scripts are meant to be run in order. Each script sources its dependencies automatically.

Script	Content
01_data_preparation.R	Load data, define item metadata, recode negatively keyed items, compute scale scores
02_item_analysis.R	Item descriptives, item histograms, corrected item-total correlations, difficulty-discrimination plots
03_scale_analysis.R	Dimension descriptives & histograms, scale intercorrelations, exploratory factor analysis (heatmap, network), parallel analysis, reliability

Big Five Dimensions

Code	Dimension	Items
EXT	Extraversion	EXT1 -- EXT10
EST	Emotional Stability	EST1 -- EST10
AGR	Agreeableness	AGR1 -- AGR10
CSN	Conscientiousness	CSN1 -- CSN10
OPN	Openness	OPN1 -- OPN10

Negatively keyed items are recoded in 01_data_preparation.R.

Required R Packages

tidyr, dplyr, moments, ggplot2, ggrepel, scales, Hmisc, psych, nFactors, qgraph

Install all at once via setup.R or manually:

install.packages(c("tidyr", "dplyr", "moments", "ggplot2", "ggrepel",
                    "scales", "Hmisc", "psych", "nFactors", "qgraph"))

License

The IPIP items are in the public domain (ipip.ori.org). The Kaggle dataset was collected by Open Psychometrics.