How were erect penis girth measurements collected in the Veale et al. nomogram study and which studies contributed the most data?
Executive summary
Veale et al. performed a systematic review and pooled data from multiple published studies to create nomograms for penile length and girth, including erect girth, drawing on up to 15,521 men from 20 studies but with fewer subjects contributing erect measurements and considerable methodological heterogeneity between studies [1] [2] [3]. The erect-girth values in the nomograms were derived by combining reported means and standard deviations across studies (weighted means and pooled SD) and simulating observations; the underlying measurements came from a mix of clinician-measured erect exams and self- or partner-measured reports, which the authors and subsequent commentators note introduces bias and limits precision [2] [4] [5].
1. How the erect girth data were built: pooling, weighting and simulation
Veale et al. did not measure thousands of men themselves; they systematically reviewed the literature, extracted reported means and SDs for erect circumference (girth) among eligible samples, calculated weighted means and pooled standard deviations across included studies, and then used a simulated sample of 20,000 observations drawn from the resulting normal distributions to construct clinical nomograms for erect girth and other dimensions [2] [1]. That approach produces a smoothed, population-level picture usable for clinical counseling, but it depends entirely on the quality, consistency and representativeness of the included study reports rather than primary re-measurement [2] [6].
2. How erect girth was measured in the original studies: methods varied and included self- and partner-measurement as well as clinical measurement
The primary studies feeding the pooled erect-girth statistic used a variety of measurement methods: some employed clinician measurement during a clinical erection or partner-assisted measurement during sexual activity, others used self- or partner-administered disposable tape measures or color‑coded measuring strips with instructions, and several studies measured erect dimensions after pharmacologically or psychogenically induced erection—details that introduce heterogeneity and potential systematic bias [5] [4] [7]. Veale et al. themselves noted that relatively few erect measurements were taken in a clinical setting, flagging this as a limitation; the meta-analysis therefore contains a mix of methods, and subsequent reviews have highlighted interobserver and self-measurement variability as a major source of error [1] [8] [9].
3. Measurement bias and variability that affect erect girth inferences
Multiple sources emphasize that self-measurement and differing measurement aids (disposable tapes, semi-rigid rulers, color-coded strips) can lead to systematic over- or underestimation, and that interobserver variability for girth can be substantial—reviewed papers report mean underestimates or variability on the order of 15–27% in some contexts—so the pooled erect-girth nomogram must be interpreted with those methodological caveats in mind [8] [5] [9]. Veale et al. also observed that erect measurements were fewer and that heterogeneity across studies was greater for some dimensions, underlining that erect-girth nomograms are approximations meant for counseling rather than precise anthropometric gold standards [1] [2].
4. Which studies contributed the most data — what the sources say and what they do not
Veale et al. report pooling data from 20 studies and up to 15,521 men overall, although later syntheses and reviews note that the effective sample for building erect nomograms relied on a smaller subset (one review cites a reliance on data from about 10,704 men for their nomogram work) and that relatively few studies measured erect dimensions in clinical settings [3] [10] [1]. The public reporting available in these sources names individual contributors (for example, a large cohort of 778 Middle Eastern men published as an erect‑dimension nomogram is one identified study that appears in later related work) but the provided documents do not include a complete, itemized table in the material supplied here showing each included study’s sample size and the exact contribution to the erect-girth pooled estimate [11] [4]. Therefore it is accurate to say Veale’s nomograms are dominated by a relatively small number of larger primary studies but the exact top contributors and their numeric weights cannot be enumerated from the provided sources alone [3] [10].
5. Bottom line and competing perspectives
The nomogram for erect girth in Veale et al. is a useful, systematically constructed clinical tool that synthesizes published data using weighted means and simulated cohorts, but it rests on heterogeneous measurement methods—self-report, partner measurement, and clinician measurement—and on a smaller number of true clinically measured erect samples, which reduces precision and invites caution in interpreting individual results; proponents argue it offers a practical reference for counseling while critics point to measurement bias and interstudy heterogeneity that limit its definitive accuracy [2] [1] [8].