Public policy still at risk from dodgy data

The ABS gave itself a pass mark of 93.3%, according to The Mandarin, “to be sure that the information is of sufficient quality”.  I am at a loss to see how 93.3% of households filling in a Census form, or any other rate for that matter, can assure that information is of sufficient quality.

For example, it could be possible that every one of the 93.3% of houses filling in the Census form has omitted one person from its list of residents. Assuming on average there are 3 persons per households, that would mean that 33% of the people in Australia were omitted from the Census. Or if every third household left out a person, then 11% of the people would have been missed. (I didn’t take into account the people in the missing 6.7% of households, so the percentage of missing people is slightly different to what I have claimed.)

Similarly, let’s say in an act of deliberate civil disobedience, every respondent deliberately gave an incorrect answer to one Census questions. Can you imagine what that would do the quality of the Census?  I can’t either, but I have little doubt that it would reduce its quality significantly.

The real problem the ABS has is that it has no way of making estimates of quality. I say this because, as I understand matters, no testing of note was undertaken prior to the Census being undertaken, which might be able to throw a little light on this issue.  Further, the Post Enumeration Survey is just a check on coverage, as there is no attempt being made to measure how well Australians answered the Census questions.

Similarly, there has been no discussion of whether or not the answers provided on a paper form are different to the answers provided online.  I don’t know what the differences might be, but I would bet there are differences which might possibly be large. How does this impact on quality? Is it the same across the whole population or is it focused into particular areas or sectors of society?

We do know the ABS has announced that a panel of “independent experts” has been asked to examine this issue and report on the quality issue early next year.  How this panel will be able to come to any credible conclusions is a mystery to me, as there is no believable evidence available.  I only hope that this panel of independent experts comes up with conclusions much closer to the truth than did the one which investigated the obviously dodgy MLFS.  It gave the MLFS a “clean bill of health” but all serious users of labour data don’t give the MLFS data much credence these days.