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Content Validity Ratio (CVR) Calculator: Lawshe, with Exact Critical Values

How do you calculate the content validity ratio?

CVR = (ne - N/2) / (N/2), where ne is the number of experts who rate the item "essential" and N is the number of experts. It runs from -1 to +1. An item is kept if its CVR reaches the critical value for that panel size: with 10 experts, 9 must say essential (CVR .80). Use the exact binomial values of Ayre and Scally (2014); the 2012 Wilson table is known to be wrong.

Most CVR tables in theses are either Lawshe's 1975 values or Wilson, Pan and Schumsky's 2012 recalculation. Ayre and Scally (2014) showed the 2012 values are wrong and "should not be used". This calculator computes the exact value for any panel size.

Enter the panel size and how many experts rated each item essential; it returns every item's CVR, keep-or-drop, and the CVI.

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Built by Muhammad Shahzeb Anwar, MSc Industrial and Organizational Psychology. Content validation of selection tests is where Lawshe's method comes from: it was published in Personnel Psychology in 1975.

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Your items

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Example ratings are filled in; replace them. Lawshe's question: is the skill or knowledge measured by this item essential, useful but not essential, or not necessary? Count only "essential".

Exact critical values (alpha = .05, one-tailed)

Experts (N)Must rate essentialCritical CVR
551.000
661.000
771.000
87.750
98.778
109.800
119.636
1210.667
1310.538
1411.571
1512.600
1612.500
1713.529
1813.444
1914.474
2015.500
2518.440
3020.333
3523.314
4026.300

From Ayre and Scally (2014), Table 2, reproduced here by exact binomial calculation. The values jump around because the binomial distribution is discrete: 13 experts need 10 (CVR .538) but 14 need 11 (CVR .571). Where you can choose the panel size, choose one where the required agreement is lower.

What went wrong with the tables

Lawshe published his critical values in 1975 without explaining exactly how they were computed. Wilson, Pan and Schumsky (2012) tried to recalculate them and published a new table, which was widely adopted. Ayre and Scally (2014) showed that the 2012 values came from a spreadsheet function misread by one and from a normal approximation without a continuity correction, and that they should not be used. The exact binomial approach used here gives the smallest number of "essential" ratings that would be unlikely (p at or below .05) if experts were guessing.

The CVI is Lawshe's content validity index: the mean CVR of the items retained. A separate tradition in nursing research uses the item-level CVI (the proportion of experts rating an item 3 or 4 on a four-point relevance scale) and the scale-level S-CVI; those are different numbers on a different rating scale.

Before you rely on this

What this will not tell you

CVR measures expert agreement, not validity in itself: a panel can agree on a poor item. It depends on the panel being genuine subject-matter experts and on Lawshe's three-option question being asked as written. The table above covers alpha = .05; the calculator computes .01 as well. Nothing you type leaves your browser.

Questions

Questions people actually ask

What is a good content validity ratio?

There is no single good value: an item is acceptable if its CVR reaches the critical value for the panel size. With 10 experts that is .80 (9 of 10 rating it essential); with 20 experts it is .50 (15 of 20).

What is the CVR critical value for 10 experts?

0.80 under the exact binomial method (9 of 10 experts must rate the item essential). Lawshe's 1975 table gave .62 and Wilson et al. (2012) gave a different figure; Ayre and Scally (2014) showed the exact value is .80.

How do you calculate the CVI from CVR?

In Lawshe's method the content validity index is the mean CVR of the items retained after the critical-value check.

Can CVR be negative?

Yes. CVR runs from -1 (no expert rates the item essential) through 0 (exactly half do) to +1 (all do).

How many experts do I need for CVR?

At least 5, but small panels need unanimity: with 5 to 7 experts every one must rate an item essential. Panels of 8 to 12 are common; check the table for sizes where the required agreement drops.

The papers behind the method

Sources

Formulas and critical values come from the original papers; each reference was checked against its DOI record on 17 October 2026.

  1. Lawshe, C. H. (1975). A quantitative approach to content validity. Personnel Psychology, 28(4), 563-575: https://doi.org/10.1111/j.1744-6570.1975.tb01393.x
  2. Wilson, F. R., Pan, W., & Schumsky, D. A. (2012). Recalculation of the critical values for Lawshe's content validity ratio. MECD, 45(3), 197-210: https://doi.org/10.1177/0748175612440286
  3. Ayre, C., & Scally, A. J. (2014). Critical values for Lawshe's content validity ratio: Revisiting the original methods of calculation. MECD, 47(1), 79-86: https://doi.org/10.1177/0748175613513808
Citation

Cite this tool

Free to use and free to quote. If a figure here is useful in something you are writing, a link back is all that is asked.

Muhammad Shahzeb Anwar, MSc Industrial and Organizational Psychology. Content Validity Ratio (CVR) Calculator. Shahzeb Speaks. https://www.shahzebspeaks.com/content-validity-ratio-calculator/

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Testing whether experts agree on ratings, not just on essential?

The free Aiken's V calculator gives an agreement coefficient with a confidence interval for ratings on any scale, the other common content-validity index in thesis work.

Open the Aiken's V calculator