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Lesson 4 of 9 · 20 min

Assess reliability and convergent validity

Evaluate indicator loadings, indicator collinearity, Cronbach’s alpha, ρA, composite reliability and AVE, and decide what to do with weak items.

Before you can trust the paths between constructs, you must show that the constructs are measured well. For reflective constructs this means four checks, in this order: indicator reliability, internal consistency reliability, convergent validity and discriminant validity (Lesson 5). Formative constructs are assessed differently, as explained at the end of this lesson.

Try it in the tool

Assess the measurement model

  1. Run the sample study, then open the Measurement tab.
  2. Check that every loading is at least 0.708 and every indicator VIF below 3.
  3. In “Construct reliability and validity”, check α, ρA and ρC (0.70–0.95) and AVE (≥ 0.50).

Step 1: indicator loadings

A loading is the correlation between an indicator and its construct. Squared, it is the share of the indicator’s variance explained by the construct. The guideline is a loading of at least 0.708, because 0.708² ≈ 0.50: the construct explains at least half of the indicator’s variance. In the sample study, all 20 loadings are between 0.814 (PE3) and 0.932 (BI1), and all are significant (p < .001, bootstrap CIs far from zero).

What if a loading is lower? Indicators between 0.40 and 0.708 should be removed only if deleting them raises composite reliability or AVE above the threshold, and if content validity does not suffer. Indicators below 0.40 should usually be removed. Report every deletion and the reason.

Indicator collinearity

The VIF column shows how much each indicator overlaps with the other indicators of its construct. For reflective items some overlap is expected; values above 5 suggest redundant wording. The highest here is BI1 at 3.32, slightly above the conservative guideline of 3 but well below 5, which is acceptable for a three-item intention scale whose items are deliberately similar.

Step 2: internal consistency reliability

ConstructItemsCronbach’s αρAρCAVE
PE40.8750.8810.9140.728
EE40.8730.8830.9120.723
SI30.8410.8650.9030.757
TR30.8490.8520.9080.768
BI30.9070.9090.9410.843
UB30.8580.8590.9140.779

Three reliability coefficients are reported in PLS-SEM, and the true reliability usually lies between them:

  • Cronbach’s alpha assumes equal loadings and is a conservative lower bound.
  • Composite reliability ρC weights indicators by their loadings and tends to be a liberal upper bound.
  • ρA (Dijkstra-Henseler’s rho) lies between them and is the recommended single measure for PLS constructs.

Values between 0.70 and 0.90 are satisfactory to good (0.60 to 0.70 acceptable in exploratory research). Values above 0.95 are problematic: they suggest redundant items, straight-lining or inflated correlations. All constructs here are between 0.84 and 0.94, so reliability is established. The Studio also provides bootstrap CIs for each coefficient; for a strict test, check that the upper bound of ρC stays below 0.95 (BI: 0.952, at the limit).

Step 3: convergent validity

Convergent validity asks whether the construct explains most of the variance of its indicators. The average variance extracted (AVE) is the mean of the squared loadings and should be at least 0.50. All AVEs here are between 0.723 and 0.843, so convergent validity is established.

Formative constructs

For a formative construct, loadings and reliability make no sense, because the indicators need not correlate. Instead, assess (1) convergent validity with a redundancy analysis against a global single item measuring the same construct (path ≥ 0.70), (2) indicator collinearity (VIF below 3, problems above 5), and (3) the significance and size of the outer weights. A non-significant weight is kept if its loading is at least 0.50 and significant; otherwise, theory decides.

Reporting

All indicator loadings exceeded 0.708 (range 0.814 to 0.932, p < .001), indicating satisfactory indicator reliability. Cronbach’s alpha (0.841 to 0.907), ρA (0.852 to 0.909) and composite reliability ρC (0.903 to 0.941) were above 0.70 and below 0.95, establishing internal consistency reliability. AVE values ranged from 0.723 to 0.843, above the 0.50 threshold, supporting convergent validity (Table 2).

For a cross-check outside the Studio, the reliability and validity tool computes α, CR, ω, AVE, Fornell–Larcker and HTMT from a CFA, the CB-SEM perspective on the same questions.

Key takeaways

  • Loadings ≥ 0.708; remove 0.40–0.708 items only if it improves CR or AVE without harming content validity.
  • Report α, ρA and ρC; aim for 0.70–0.90 and stay below 0.95.
  • AVE ≥ 0.50 establishes convergent validity.
  • Formative constructs need redundancy analysis, VIF and weight significance instead.

Check your understanding

Answer each question to see the explanation. Finishing the quiz marks this lesson as complete.

Q1Why is 0.708 the guideline for indicator loadings?
Q2A construct has ρC = 0.97. What does this suggest?
Q3What is the AVE?
Q4Which criterion is NOT used to assess a formative measurement model?