| There is still, however, a considerable margin of self-selection of American economic leadership. |
| This self-selection does represent a potential bias, since participants have been self-selected on the basis of interest and, possibly, prior experience. |
| A self-selection sample was used to recruit 108 participants for this study. |
| You might well select another career for yourself — but you wouldn't exactly call it self-selection. |
| As participation in challenge testing at all time points was voluntary, self-selection was a possible confounder. |
| I wasn't going to go on this track, but I find it interesting that there's screening in the U. S. and self-selection here in Canada. |
