It's risen by 1 percentage point since 2012 when they started tracking this, and for millennials, the number is around 8.2%. They don't seem to have data for zoomers yet. [1] This would suggest (imo) that 4.5% is in fact a significant underestimate, but I don't know necessarily that it's as far off as 20%
Its also important to remember that as humans we tend to vastly over-estimate the incidence of relatively rare things. We tend to think that something happens based on how often we encounter it, without considering the total number of encounters.
4.5% is about 1 in 22. 8.2% is 1 in 12. Even accounting for the fact that most LGBT people are as private about their sexuality as straight people are, its often enough that you're likely to encounter LGBT people on a frequent basis.
Also, the "what's your estimate" question specifies "gay or lesbian", whereas the self-identity question apparently includes the B and T. Obviously this would make the high estimate for just "gay or lesbian" even further off, but it still doesn't say anything good about the article's conclusion.
Maybe a minor point, but I think sexual fluidity remains under-addressed by these polls. Some people are, for all intents and purposes, identifying as LGBT during, say, their college years, but then go on to settle down with an opposite-sex spouse.
If the person once identified as LGBT, but doesn't today, is it based on what they "actively" are? Or if you ever once identified as LGBT, for purposes of polling, you remain in that category for life?
Not a minor point at all. I think sexual fluidity is one of the most relevant aspects of sexuality and I would love to see it measured. Labels like "Gay" and "Bi" are way too simplistic.
The medical terminology is better, its often "Men who have sex with men" or something similar that removes the need to understand the subjects mental state and simply focus on the important clinical data.
That's better, but doesn't separate men who have sex with manly men from those who only have sex with traps. It also excludes those who don't have sex at all for one reason or another.
[1]: https://news.gallup.com/poll/234863/estimate-lgbt-population...