The most parsimonious explanation for a big miss is measurement error, but there is a trend worth watching.
The advantage of these moving averages is that they smooth out both seasonal fluctuations and simple measurement error.
What really interest me about this is that, entirely independently, the same explanation is made for the measurement error here.
Much of the placebo effect seen in clinical trials is the combination of the natural tendency of patients to get better and measurement error.
It would also mean that any unavoidable measurement error has a similar impact along the whole spectrum of marks, rather than being concentrated around grade boundaries.
But the implications of this had, to date, "not been well-presented to government, nor have issues of measurement error and the implications these have for performance tables".
BBC: NEWS | UK | Education | School standard rise 'overstated'
People who do actually know their physics have made the same point: that what has been discovered is a measurement error, not a flaw in the basic theory.
The trouble is that the longer the puzzle continues, the more potentially worrying it becomes, because it becomes less and less likely that simple measurement error explains it.
We develop a statistical framework that uses lights growth to augment existing income growth measures, under the assumption that measurement error in using observed light as an indicator of income is uncorrelated with measurement error in national income accounts.
Other wrinkles complicate response-time measurement, such as human error.
"The scientists are right to be extremely cautious about interpreting these findings, " said Jim Al-Khalili, a physicist from the University of Surrey, who suggested that a simple error in the measurement is probably the source of all the fuss.
But the strategy worked, because United States agencies were allowed to proceed by trial and error, continually adjusting their policies over time in response not to ideology but to hard measurement of the results against societal goals.
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