CRP 2026: Scale Reliability
Scale reliability is assessed using (α), the most widely used measure of internal consistency. A coefficient of α ≥ 0.70 is generally considered acceptable for research purposes (Nunnally & Bernstein, 1994), while values above 0.80 indicate good to excellent reliability.
All three TABS constructs demonstrate excellent internal consistency across the CRP 2026 frozen dataset, with every Cronbach’s alpha exceeding 0.82 across all three sample definitions. This indicates that the survey items within each construct are measuring the same underlying factor reliably, regardless of which inclusion criteria are applied.
Cronbach’s Alpha by Construct and Sample
| Construct | Conservative Clean N=79 | Flexible Clean N=116 | Prolific Accepted N=200 |
|---|---|---|---|
| Barriers | 0.8572 | 0.8691 | 0.8728 |
| Readiness | 0.8762 | 0.9052 | 0.9171 |
| Maturity | 0.8368 | 0.8761 | 0.8847 |
Bootstrap Confidence Intervals on Alpha
Point estimates of Cronbach's alpha can fluctuate with sample composition. Bootstrap percentile confidence intervals (Efron, 1979) quantify that uncertainty: if the entire CI sits above the .70 acceptability threshold (or .80 for "good"), the scale's reliability is well-supported across plausible resamples of the data.
| Construct | Bootstrap mean | 95% CI lower | 95% CI upper | CI width |
|---|---|---|---|---|
| Barriers | 0.8723 | 0.8438 | 0.8963 | 0.0525 |
| Readiness | 0.9159 | 0.8962 | 0.9328 | 0.0366 |
| Maturity | 0.8838 | 0.8528 | 0.9088 | 0.0560 |
Bootstrap percentile CIs computed from 1,000 resamples (Efron, 1979). Narrow CIs that do not cross the .70 acceptability threshold provide stronger evidence of scale reliability than a single point estimate.
Alpha if Deleted
For each construct, alpha-if-deleted reports the value Cronbach's alpha would take if a given item were removed from the scale. Items whose removal would noticeably raise alpha are candidates for revision in a future version of the instrument; items whose removal would lower alpha are well-aligned with the construct.
Barriers (base alpha = 0.8728)
1 item would raise alpha if removed. None of these are large enough to motivate dropping the item, but they are the candidates a future revision would target first.
- Cybersecurity Concerns: alpha if deleted = 0.8747 (change +0.0019)
Readiness (base alpha = 0.9171)
No items would raise alpha if removed. Closest call: Budget Adequacy (alpha if deleted = 0.9171, change +0.0000). The scale is robust to single-item removal.
Maturity (base alpha = 0.8847)
No items would raise alpha if removed. Closest call: Process Mgmt & Standardization (alpha if deleted = 0.8761, change -0.0086). The scale is robust to single-item removal.
Reliability by Demographic Group
Cronbach's alpha computed within each organizational subgroup. Comparable values across SMB vs Enterprise and For-Profit vs Non-Profit / Government provide evidence that the scales work reliably regardless of organizational context, supporting cross-segment comparisons in downstream analyses.
| Group | N | Barriers | Readiness | Maturity |
|---|---|---|---|---|
| SMB (<1000 emp) | 114 | 0.8628 | 0.9107 | 0.8692 |
| Enterprise (>=1000 emp) | 86 | 0.8865 | 0.9247 | 0.8985 |
| For-Profit | 151 | 0.8765 | 0.9267 | 0.8888 |
| Non-Profit / Gov | 49 | 0.8664 | 0.8746 | 0.8723 |
Cronbach's alpha computed independently within each demographic group. Stable values across groups demonstrate that the scales perform reliably regardless of organizational size or sector.
Interpretation
Several key observations emerge from the reliability analysis:
- All alphas exceed 0.82, well above the commonly cited 0.70 threshold, indicating excellent internal consistency across all constructs and samples.
- Reliability coefficients are stable across sample definitions, meaning the scales perform consistently whether computed on the strictest clean sample or the full CRP dataset.
- Alpha values tend to increase slightly with larger sample sizes, which is expected behavior and does not indicate measurement problems.
- The Readiness construct shows the highest alphas (up to 0.9171), while Maturity shows the lowest (still above 0.8368), which may reflect the smaller number of items in the Maturity scale (9 vs. 18-19).
The consistency of these results across three sample definitions demonstrates that the TABS scales are reliable instruments regardless of the inclusion criteria applied. This robustness is critical for supporting any downstream inferential analyses.
References
- Cronbach, L. J. (1951). Coefficient alpha and the internal structure of tests. Psychometrika, 16(3), 297-334.
- Nunnally, J. C., & Bernstein, I. H. (1994). Psychometric theory (3rd ed.). McGraw-Hill.
Related
- Descriptive Statistics - means, SDs, and correlations for each construct
- CRP 2026 Overview - frozen dataset methodology and download
- Data Quality Pipeline - how the samples are defined and validated
- ← Back to CRP 2026 Overview