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Exploratory Factor Analysis

Interim analysis from an ongoing dissertation study. Data collection is still in progress, and this work is not published.

Status

Interim. The results here are based on the responses collected so far. They may change as more data comes in, and nothing here should be treated as final.

What is in this repository

File What it is
Phase_3_analysis.jasp JASP file with the analysis and all output tables
Item_Mapping.docx Document comparing the expected item grouping with the factor results

A note on what has been removed

The survey items and the names of the constructs have been removed from everything in this repository. The instrument is still under development and is not yet published, so items are referred to only by their variable codes (for example Q9_1, Q10_6).

This means the analysis can be read and checked, but the instrument itself is not reproduced here.

Method

  • 39 items, each answered on a 1–5 scale
  • Sample: 239 completed responses, no missing values
  • Software: JASP
  • Extraction: principal axis factoring
  • Rotation: oblimin (oblique)

Principal axis factoring was used because the items are not normally distributed, which is expected for Likert data. An oblique rotation was used because the dimensions were expected to be related rather than independent.


Results

1. Descriptive statistics

All 39 items have 239 valid responses and no missing values. Every item uses the full 1–5 range.

Standard error of skewness is 0.157 and standard error of kurtosis is 0.314 for every item.

Item Mean SD Skewness Kurtosis Shapiro-Wilk W p
Q9_1 2.431 1.320 0.670 -0.707 0.853 < .001
Q9_2 2.778 1.318 0.360 -1.073 0.882 < .001
Q9_3 2.715 1.284 0.377 -0.945 0.892 < .001
Q9_4 1.828 1.092 1.243 0.736 0.754 < .001
Q9_5 2.548 1.208 0.521 -0.672 0.885 < .001
Q9_6 3.029 1.255 0.112 -1.004 0.907 < .001
Q9_7 3.498 1.263 -0.412 -0.971 0.881 < .001
Q10_1 2.916 1.178 0.257 -0.910 0.901 < .001
Q10_2 2.946 1.316 0.190 -1.183 0.891 < .001
Q10_3 2.335 1.211 0.835 -0.218 0.844 < .001
Q10_4 2.749 1.295 0.453 -0.917 0.879 < .001
Q10_5 2.259 1.170 1.021 0.300 0.820 < .001
Q10_6 2.598 1.289 0.487 -0.871 0.880 < .001
Q10_7 2.402 1.266 0.825 -0.304 0.841 < .001
Q10_8 1.933 1.179 1.231 0.614 0.766 < .001
Q10_9 2.598 1.246 0.391 -0.836 0.895 < .001
Q10_10 2.544 1.242 0.549 -0.662 0.882 < .001
Q10_11 1.874 1.042 1.446 1.922 0.762 < .001
Q10_12 2.715 1.217 0.335 -0.869 0.900 < .001
Q10_13 2.285 1.175 0.997 0.252 0.824 < .001
Q11_1 2.937 1.223 0.232 -1.025 0.897 < .001
Q11_2 2.251 1.179 0.990 0.232 0.827 < .001
Q11_3 2.042 1.137 1.198 0.788 0.795 < .001
Q11_4 2.318 1.202 0.728 -0.351 0.862 < .001
Q11_5 2.289 1.165 0.641 -0.458 0.869 < .001
Q11_6 2.590 1.270 0.411 -0.898 0.890 < .001
Q11_7 2.393 1.201 0.658 -0.439 0.873 < .001
Q11_8 2.498 1.152 0.438 -0.609 0.896 < .001
Q11_9 3.628 1.226 -0.609 -0.648 0.869 < .001
Q11_10 2.887 1.216 0.190 -0.949 0.908 < .001
Q11_11 2.013 0.981 1.349 2.035 0.783 < .001
Q12_1 2.326 1.001 0.778 0.412 0.863 < .001
Q12_2 2.264 1.120 0.588 -0.581 0.869 < .001
Q12_3 2.213 1.096 0.783 0.034 0.860 < .001
Q12_4 1.665 0.858 1.670 3.500 0.723 < .001
Q12_5 2.075 1.128 0.950 0.108 0.826 < .001
Q12_6 2.460 1.099 0.466 -0.469 0.895 < .001
Q12_7 2.226 1.049 0.815 0.355 0.860 < .001
Q12_8 2.523 1.236 0.647 -0.507 0.871 < .001

Normality. All 39 items return p < .001 on Shapiro-Wilk, so none is consistent with a normal distribution. This is expected for five-point Likert items and is why principal axis factoring was used rather than maximum likelihood.

By magnitude the departures are more modest. Seven items fall outside a skewness range of −1 to +1, and two items fall outside a kurtosis range of −2 to +2.

Items outside range Which
Skewness beyond ±1 7 Q9_4, Q10_5, Q10_8, Q10_11, Q11_3, Q11_11, Q12_4
Kurtosis beyond ±2 2 Q11_11, Q12_4

Q12_4 is the most extreme item on every distributional measure: the lowest mean (1.665), the smallest standard deviation (0.858), the highest skewness (1.670), the highest kurtosis (3.500) and the lowest Shapiro-Wilk W (0.723).

2. Factorability

Test Result
Kaiser-Meyer-Olkin (overall MSA) 0.922
Bartlett's test of sphericity χ² = 5193.286, df = 741, p < .001

Both tests pass comfortably. An overall MSA of 0.922 falls in the highest conventional band, and Bartlett rejects the hypothesis that the correlation matrix is an identity matrix.

Item-level measures of sampling adequacy:

Item MSA Item MSA Item MSA Item MSA
Q9_1 0.922 Q10_4 0.946 Q11_1 0.944 Q11_11 0.920
Q9_2 0.952 Q10_5 0.953 Q11_2 0.927 Q12_1 0.892
Q9_3 0.943 Q10_6 0.949 Q11_3 0.924 Q12_2 0.812
Q9_4 0.848 Q10_7 0.937 Q11_4 0.947 Q12_3 0.800
Q9_5 0.920 Q10_8 0.834 Q11_5 0.834 Q12_4 0.811
Q9_6 0.938 Q10_9 0.817 Q11_6 0.965 Q12_5 0.691
Q9_7 0.918 Q10_10 0.947 Q11_7 0.957 Q12_6 0.729
Q10_1 0.919 Q10_11 0.881 Q11_8 0.869 Q12_7 0.927
Q10_2 0.930 Q10_12 0.940 Q11_9 0.943 Q12_8 0.951
Q10_3 0.943 Q10_13 0.951 Q11_10 0.932

Item MSA ranges from 0.691 (Q12_5) to 0.965 (Q11_6). Q12_5 is the only item below 0.70. The lowest values cluster in the Q12 block.

3. Number of factors

Three factors were retained. The scree plot with parallel analysis is included in the JASP file.

SumSq. loadings Proportion var. Cumulative
Unrotated
Factor 1 12.743 0.327 0.327
Factor 2 3.510 0.090 0.417
Factor 3 1.366 0.035 0.452
Rotated
Factor 1 10.192 0.261 0.261
Factor 2 4.899 0.126 0.387
Factor 3 2.528 0.065 0.452

The three factors together explain 45.2% of the variance. After rotation the first factor accounts for 26.1%, the second 12.6% and the third 6.5%.

4. Factor loadings

Oblimin rotation. Loadings below approximately 0.40 are suppressed, so a blank cell is a small loading rather than a zero. Uniqueness is the proportion of an item's variance not explained by the three factors.

Item Factor 1 Factor 2 Factor 3 Uniqueness
Q9_6 0.838 0.383
Q9_7 0.816 0.466
Q9_2 0.774 0.484
Q10_6 0.767 0.358
Q11_1 0.766 0.405
Q10_7 0.756 0.344
Q9_3 0.711 0.411
Q10_2 0.686 0.423
Q10_10 0.645 0.494
Q10_5 0.625 0.453
Q9_1 0.622 0.606
Q12_8 0.618 0.534
Q10_3 0.601 0.517
Q11_9 0.587 0.600
Q10_1 0.556 0.536
Q10_12 0.539 0.565
Q10_4 0.527 0.508
Q11_7 0.508 0.466
Q10_13 0.430 0.439 0.427
Q11_6 0.426 0.570
Q12_4 0.707 0.542
Q10_11 0.702 0.514
Q12_5 0.606 0.665
Q11_3 0.580 0.455
Q10_8 0.576 0.610
Q12_6 0.542 0.721
Q11_11 0.509 0.365
Q11_2 0.497 0.592
Q11_5 0.496 0.633
Q12_2 0.491 0.762
Q9_4 0.450 0.753
Q10_9 0.442 0.622
Q12_1 0.418 0.644
Q12_7 0.512 0.452
Q11_10 0.419 0.637
Q9_5 0.758
Q11_4 0.474
Q11_8 0.738
Q12_3 0.894

5. Summary of the solution

Count
Items loading on Factor 1 only 19
Items loading on Factor 2 13
Items loading on Factor 3 only 2
Items loading on two factors 1
Items with no loading above the threshold 4
Total 39

Points to note:

  • The three factors do not correspond to the four dimensions the instrument was designed around. Factor 1 draws items from all four.
  • Factor 3 has only two items loading on it cleanly, which is below the usual minimum of three for a stable factor. It also explains the least variance at 6.5%.
  • Q10_13 loads on two factors at almost the same strength: 0.430 on Factor 1 and 0.439 on Factor 3. Whether Factor 3 reaches three items depends on how this one item is assigned.
  • Four items do not reach the threshold. Uniqueness distinguishes two situations among them: Q12_3 (0.894), Q9_5 (0.758) and Q11_8 (0.738) share very little with the rest of the set, while Q11_4 (0.474) has variance that is shared but spread across factors rather than concentrated in one.
  • Q11_11 has the lowest uniqueness in the solution at 0.365 and Q12_3 the highest at 0.894.

Reuse

This is unpublished dissertation work. Please do not reuse or cite it without asking first.

Contact

This is work in progress and feedback is welcome — umerfarooq@tamu.edu

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