Two kinsey researchers (Gebhard & Johnson) carried out a penis size survey in 1979. The methodology was a self reported penis size measurement. They asked men “How long is your penis, measuring on the top side from your belly out to the tip?”. Then, the volunteers had to do two marks on pre-stamped card. One mark was for the flaccid state and another one was for the erect penis length state. Then, the volunteers had to send the cards to the Kinsey institute. Approximately 2500 men took part in the research.
Additionally, during interviews with 4000 men, the investigator asked “the subject to estimate his penis size.” The researcher hold the ruler and the volunteer estimated his penis size.
The Kinsey researchers concluded the average erect penis length is between 5 and 6.5 inches
Opinion:
I don’t know where i should start. First of all, the self reported method should be totally rejected. It is not a reliable methodology. Men may emphasize their penis size or make a mistake. writing a mark on a card isn’t a precise measurement. So, even if there were a great number of participants, it is useless if the gathered data are not precise. Then, there is an interview with 4000 men. Once again the participants have been asked to estimate their own penis size. The margin of error may be important. In the new penis size studies, medical staff are performing the measurements. For instance, in a Israeli study, the same practitioner performed all measurements to reduce the margin of error and get data integrity. Furthermore, two methodologies have been used. I don’t know how the two sources of data have been re conciliated.
At last, i think the methodology description is no precise enough. We don’t know EXACTLY how the men were asked to measure their penis size to write it on the card and how they were asked to estimate their penis size. There is a grey area around the two methodologies. We don’t know if we speak about bone pressed measurement or non bone pressed measurement. We don’t know if the penises have been measured on the dorsal aspect…etc…etc…
So we don’t know if it benefited or not the US average erect penis size but we think the methodology was wrong. Thus, this Kinsey institute research results shouldn’t be cited when we speak about average erect penis size.
Bottom line, the Kinsey institute website also speak about another penis size research carried out in 1993 and concluded average erect penis size is 122mm (4.8 inches) but there is no additional information about it. They kinsey institute website mentions this study has never been published.
Because of the lack of accurate methodology, we didn’t include any information from the Kinsey report or further Kinsey institute research in our Ebook. If you are a man, we don’t advise you to compare your penis size to the Kinsey institute penis size average and also the Lifestyles condom study.
On the other hand, we based our research on the 1996 US journal of Urology (dr Wessels) penis size study. From the medical paper, we extracted the penis length size of each successful participant and then, we created a penis size distribution. All of that has been compiled in the Ebook.
The Wessels study said average erect penis length is equal to 13 cm (5″) bone pressed. It is confirmed by an Israeli study. The average erect penis length to be equal to 13.5 cm (5.3″) bone pressed in the Israeli study. Measurements are very similar.