changepoint

A recent US EPA study has found a distinct "changepoint" year - or spike - in autism in California and elsewhere and concludes that it would be "prudent to assume that at least some portion of this increase is real and results from environmental factors."

EPA Study: Autism Boom Began in 1988, Environmental Factors Are Assumed 2010

And now that we have a "changepoint" of 1988, we should go back and look at vaccine exposures both pre - and post - changepoint.

EPA Study: Autism Boom Began in 1988, Environmental Factors Are Assumed 2010

A recent US EPA study found a distinct "changepoint" year in autism and concludes that it would be "prudent to assume ... a portion of this increase results from environmental factors."

The Full Feed from HuffingtonPost.com David Kirby 2011

The step function's changepoint was determined by spline regression.

Howard Steven Friedman: Google Ranking The Presidents Howard Steven Friedman 2011

The step function's changepoint was determined by spline regression.

Howard Steven Friedman: Google Ranking The Presidents Howard Steven Friedman 2011

In California, the rate spiked from 5. 7-per-10,000 before the changepoint, to 20. 8-per 10,000 in its wake, and the worldwide dataset showed a similar jump (from 6.0 to 24.2).

EPA Study: Autism Boom Began in 1988, Environmental Factors Are Assumed 2010

(A study in Japan from 1988-1996 showed continuously increasing autism rates, but no calculable changepoint year - please see the full report for a discussion on study limitations).

EPA Study: Autism Boom Began in 1988, Environmental Factors Are Assumed 2010

Meanwhile, the scientists were surprised to find such similar changepoint years in California, Denmark and the worldwide dataset, although they conceded the data were consistent with similar studies done in Minnesota and Sweden, and a third US nationwide study which found, "the greatest increase in ASD prevalence occurring in cohorts born between 1987 and 1992."

EPA Study: Autism Boom Began in 1988, Environmental Factors Are Assumed 2010

Any candidate must be a substance or substances whose exposure level dramatically increased in developed countries beginning at the 1988 changepoint.

EPA Study: Autism Boom Began in 1988, Environmental Factors Are Assumed 2010

Since all difference series are comprised of values from two series, a changepoint date in any one difference series is temporarily attributed to both station series used to calculate the differences.

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