A total of 406 people responded to the survey, so it is a useful sample size. A significant majority of respondents were males in their twenties, which is not really surprising - males are more commonly affected by colour blindness than females, and the poll was conducted as an on-line survey, so some internet-savvy was required to even be aware of the poll, and then to complete it.
And the results of the survey?
In a nutshell - they really do work, for the majority of users.
You really need to read the whole article to get the full picture, but the Conclusion sums it up pretty well:
The work by Blake Porter is licensed under a Creative Commons Attribution-Non Commercial-ShareAlike 4.0 International License