Thursday, 22 July 2010

Ladders and measurement error

I'd noted yesterday a rather nice piece looking at SES and health outcomes showing that self-perceived status does more to drive health outcomes in one experiment than do objective markers of health status. The result could reflect measurement error in the objective markers or it could reflect that folks place different weights on different aspects of status when deciding on their self-perceived status.

LemmusLemmus pointed out in the comments there that the self-perceived status question was prefaced by a primer having respondents think about their income, education and occupation: "where they stand compared to other persons in the United States in terms of income, education, and occupation". So it's relatively weak support for the multiple ladders hypothesis which, if respondents took the priming seriously, would then only reflect different weightings across those three potential status components. The test isn't strong enough to distinguish much between measurement error and multiple status ladders (or, rather, differentially weighted status ladders).

So an interesting test of measurement error versus more ladders would be a repeating of the experiment but priming different respondents with different versions of the the question above. For some, no primer would be given. For others, the three above. And for a third group, a much broader set. If the no-primer or thick-primer treatments strengthened the effect of self-perceived status relative to the objective markers, then that supports the multiple ladders hypothesis. If self-perceived status does best when the primer relates directly to the objective measures (as opposed to a no primer or thick primer version), then it's probably measurement error.

Little chance the study would be repeated in this way, but at least it's testable in principle.

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