Controlled studies are the only way to get accurate results, since many men are prone to exaggeration
"Several scientific studies have been performed on the erect length of the adult penis.
Studies which have relied on self-measurement, including those from Internet surveys, consistently reported a higher average length than those which used medical or scientific methods to obtain measurements.
The following staff-measured studies are each composed of different subgroups of the human population (i.e. specific age range and/or race; selection of those with sexual medical concerns or self selection) which may meet the definition of possible sample bias.
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A study published in the September 1996 Journal of Urology concluded that average erect length was 12.9 cm (5.08 in) (measured by staff). The purpose of the study was to provide guidelines of penile length and circumference to assist in counseling patients considering penile augmentation.
Erection was pharmacologically induced in 80 physically normal American men (varying ethnicity, average age 54). It was concluded: Neither patient age nor size of the flaccid penis accurately predicted erectile length.
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A study published in the December 2000 International Journal of Impotence Research found that average erect penis length was 13.6 cm (5.35 in) (measured by staff). Quote: "The aim of this prospective study was to identify clinical and engineering parameters of the flaccid penis for prediction of penile size during erection."
Erection was pharmacologically induced in 50 Jewish Caucasian patients who had been evaluated for Erectile dysfunction (average age 47±14y).
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A study conducted by LifeStyles Condoms found an average of 14.9 cm (5.9 in) with a standard deviation of 2.1 cm (0.8 in) (measured by staff). The purpose of this study was to ensure properly sized condoms were available.
401 college students volunteered to be measured during 2001 Spring Break in Cancún, Mexico, of which 300 gained an erection to be clinically measured (without pharmacological aid). The 300 effective measurements makes this study double the size of any prior study that uses medical staff to measure penis size.
Erect circumference
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A study conducted by LifeStyles Condoms during 2001 Spring Break in Cancún found an average of 12.6 cm (5.0 in) with a standard deviation of 1.3 cm (0.5 in).
Similar results exist regarding studies of the circumference of the adult fully erect penis, with the measurement taken mid-shaft.[citation needed]
As with length, studies that relied on self-measurement consistently reported a higher average than those with staff measuring."
Human penis size - Wikipedia, the free encyclopedia
