Level of Confidence

[CynthiaSwain]

My users want to look at the spatial distribution of the percent of households that receive a particular government benefit, within block groups, across Boulder County, in 2010, and plan a marketing campaign for 2012. County wide, we have 404 households receiving this benefit out of 27,853 eligible households. How can I calculate the level of confidence we should have using this 2010 data to predict the pattern in 2012?

[EricKrause]

This is an deceptively complicated question.

Let's try to narrow things down.  Are you trying to predict the proportion of households (in each block group) that will receive this benefit in 2012?  And you're trying to predict this proportion from data taken in 2010?

Assuming this is correct, you need to build some kind of model for making these predictions.  The statistical errors of this model will dictate the appropriate level of confidence (doubling the standard error is a common method).  As for how you would build this model, I really don't have any good recommendations.  You need to talk to a statistician that specializes in population dynamics over time.

[CynthiaSwain]

Thank you for your time and response. I didn't go into detail in my first message, but my users want to look at the percent of households receiving a benefit for each block group (number of households receiving the benefit out of number of eligible households), then target market those block groups with low percents in 2012. My suspicion is that we don't have enough observations (404 households receiving this benefit out of 27,853 eligible households) to chop them up into 191 block groups. I'm still not sure how to proceed, but will look into the interpretation of the statistical error of a model, to see if this will help. Again, thanks so much for your answer.