What populations and methods did John Wessells use in his penile length research and year?

1. How Wessells measured men — the protocol that became a reference point

Wessells’ 1996 J Urol study described a standardized measurement protocol that subsequent reviews cite as the reference: measurements from suprapubic skin to distal glans for flaccid length, a maximally stretched flaccid length obtained by gently pulling the glans to mild discomfort, and erect length measured after pharmacologic induction or self‑stimulation; mid‑shaft circumference was recorded with a tape ^[1]. The 1996 sample consisted of 80 adult urology patients (mean age 54, range 21–82) measured by a single trained examiner, which the literature later used to justify comparing stretched length as a surrogate for erect length because the study reported a close correlation between stretched and erect measures ^{[1] [2]}. This standardized approach addressed measurement variability and is repeatedly cited in systematic reviews as the methodological baseline ^{[2] [1]}.

2. Who was studied — US clinical patients versus Jordanian cohorts

The 1996 paper sampled 80 physically normal adult men treated in a U.S. urology setting, producing the canonical averages reported above ^{[1] [2]}. By contrast, a later study attributed to Wessells in the International Journal of Impotence Research (2005; online preview Oct 28, 2004) examined two distinct Jordanian groups: 271 adults with normal erectile function and 109 adults presenting with impotence, with measurements including flaccid and stretched lengths for both groups and pharmacologically induced erect length for the impotence group ^[3]. These differences matter because population characteristics (age, clinic recruitment, geographic ancestry, presence of erectile dysfunction) influence mean values and the interpretation of what constitutes “average” penile dimensions, yet some summaries collapse these studies into a single normative figure without noting the distinct cohorts ^{[3] [1]}.

3. What the numbers show — reported averages and correlations

Wessells’ U.S. cohort reported mean values of 8.8 cm flaccid, 12.4 cm stretched, and 12.9 cm erect, and concluded stretched length closely approximated erect length, supporting the use of stretched measurement as a practical proxy ^{[2] [1]}. The Jordanian study reported a larger, more heterogeneous dataset with separate reporting for men with normal function versus impotence and included additional metrics such as mid‑shaft circumference and patient height, expanding the descriptive picture ^[3]. Review articles and meta‑analyses have used Wessells’ 1996 protocol and means as reference points, but they also pool many studies with different methods and dates, which produces a range of normative estimates and temporal trends not captured by any single Wessells paper ^{[1] [4]}.

4. Why methods and cohorts change the headline conclusions

Measurement technique, examiner training, pharmacologic induction versus spontaneous erection, and sample source (clinical patients vs population samples; country of origin) shift mean values and variation. Wessells’ 1996 work emphasized measurement standardization with a single trained examiner, which reduces within‑study variability but limits generalizability beyond the clinic cohort ^[1]. The 2004/2005 Jordanian paper broadened geographic representation and introduced impotence cohorts, which affects averages and the relevance of stretched‑to‑erect correlations ^[3]. Systematic reviews that aggregate many studies highlight temporal and methodological heterogeneity, and they note that erect length estimates change when older, smaller studies are combined with more recent, larger samples ^[4].

5. What readers should take away — context, not a single norm

Wessells’ 1996 study is a methodological touchstone: it sampled 80 men in the U.S., used a trained examiner, and reported mean flaccid/stretched/erect lengths that have been widely quoted ^{[1] [2]}. A later Jordanian study (2004/2005) expanded on methods and populations, demonstrating that population and recruitment differences materially affect reported averages ^[3]. When interpreting headline numbers, readers must prefer contextualized comparisons that state sample size, recruitment setting, measurement method, and year; failing to do so risks presenting a single “normal” value that obscures real variation across populations and methods ^{[1] [3]}.