Just out of interest, what’s your prediction of the sample mean AQ for those responses to my survey that are submitted after I put the note at the top of the post asking only previous non-responders to respond, assuming I get more than, say, 5?
It’s hard to say, since the new set of respondents could have the same selection bias. They would be people who 1) opened your “Do you have High-Functioning Asperger’s Syndrome?” post, 2) read the last paragraph of the post which mentioned the poll, 3) considered taking the poll but didn’t, 4) opened this post about the Asperger’s poll (or re-opened your previous post) and saw your request, and 5) decided to comply with your request and take the poll. Steps 1, 2, and 4 all seem likely to select for high-AQ people; steps 3 & 5 might shift your sample in the opposite direction but probably not as strongly (although the explicit concerns about nonresponse bias could make low-AQ people especially motivated to take the survey to counteract that bias).
To answer your question, I’ll guess that the new mean will be slightly lower than the first result but not by much. Let’s say a mean of 25 for your new sample, and a mean of 21 if we ever give this survey to a representative sample of the LW community (or at least a sample that doesn’t know that the survey is about Asperger’s).
Just out of interest, what’s your prediction of the sample mean AQ for those responses to my survey that are submitted after I put the note at the top of the post asking only previous non-responders to respond, assuming I get more than, say, 5?
It’s hard to say, since the new set of respondents could have the same selection bias. They would be people who 1) opened your “Do you have High-Functioning Asperger’s Syndrome?” post, 2) read the last paragraph of the post which mentioned the poll, 3) considered taking the poll but didn’t, 4) opened this post about the Asperger’s poll (or re-opened your previous post) and saw your request, and 5) decided to comply with your request and take the poll. Steps 1, 2, and 4 all seem likely to select for high-AQ people; steps 3 & 5 might shift your sample in the opposite direction but probably not as strongly (although the explicit concerns about nonresponse bias could make low-AQ people especially motivated to take the survey to counteract that bias).
To answer your question, I’ll guess that the new mean will be slightly lower than the first result but not by much. Let’s say a mean of 25 for your new sample, and a mean of 21 if we ever give this survey to a representative sample of the LW community (or at least a sample that doesn’t know that the survey is about Asperger’s).
The results of the new survey will, I am sure, be enlightening!