Talk:Selection bias

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[edit] Removing Selection Bias?

Might be handy if this page included some information about removing selection bias - but I don't have the knowledge. Cached 11:42, 5 December 2005 (UTC)

I just started a new section on this. Tobacman 20:08, 11 January 2006 (UTC)

[edit] "Selection bias" vs "sampling bias"

I believe that much of this article as written so far pertains to sampling bias, not selection bias, and hence the article clamors for substantial revision. Properly, selection bias refers to bias in the estimation of the causal effect of a treatment because of heterogeneous selection into the group that receives the treatment. Sampling bias refers to biases in the collection of data. (See also the article on bias (statistics).) Tobacman 20:08, 11 January 2006 (UTC)

[edit] Self-selection Bias in Online Polling

I am interested in ttesting the validity of online polling, under which the assumption is made that the set of participation in a poll is defined by the persons who view the website for other reasons, and who participate in the poll based upon their discovery of its presence.

I am especially interested in determining the validity of such a sample when affected by a self-selection bias, particularly when a subset of participants with a predetermined answer to a poll, is selected by self-recruitment - that is, by other means than discovery only upon visitation of the website, such as mutual e-mail notification.

To what degree can such participants bias the results of the poll, in comparison to their relative participation?

Any thoughts on approach?

Nothing apart from appreciating

Heckman was is smart, yes. why doesnt he make his model clear for public consumption. Its too mathematical.

Stephen mpumwire, Fortfortal