A cruise around the UC Davis site reveals a recurring theme of sponsorship, donation and subscription. Of course $$$$$$$$$ is the theme of every aspect of American life, but to British eyes, UC Davis looks like a particularly mercenary place.
If statistics are as much fun to you as they are to me, you're going to have a great time reading the following.
Suppose we are talking about something which is less emotive, such as a persons height.
"To understand the fallacy of the conclusion, consider the following analogy, based on male height and graphically illustrated in Figure 1. Suppose the criterion for “tall” was 74.5 in. and taller in the mid-1980s, but the criterion was loosened to 72 in. and taller in the mid-1990s. A diagnostic instrument based on the looser, more recent criterion of 72 in. would identify males who met the 74.5-in. criterion as well as those who met the 72-in. criterion.1 Although a perfectly reliable diagnostic instrument based on a looser criterion would identify 100% of the individuals who meet the looser criterion along with 100% of the individuals who meet the more restricted criterion, a highly reliable instrument might identify about 90% of each group; this is the percentage of each cohort in the California study who met the more recent autism criteria.
Most crucially, broadening the criterion will result in a dramatic increase in diagnosed cases. For instance, census data allow us to estimate that 2,778 males in McClennan County, Texas would be called tall by the more restricted 74.5-in. criterion, and 10,360 males would be called tall by the broader 72-in. criterion; if those two criteria had been applied a decade apart, a 273% increase in the number of males called tall would have emerged—without any real increase in Texans’ height. In the same way, the 273% increase from 2,778 versus 10,360 California children who received services for “autism” in 1987 versus 1998 could well be a function of broadened criteria.
As we have already detailed, the commonly applied diagnostic criteria for autism broadened nationally from the 1980s to the 1990s; thus, it would be unusual if the criteria used for eligibility in California had not also broadened during this time. Two further aspects of the California data suggest that the criteria must have broadened. First, children in the more recent cohort were dramatically less likely to have intellectual impairment: Whereas 61% of the children in the earlier cohort were identified as having intellectual impairments, only 27% of the children in the more recent cohort were so identified. The lower rate of intellectual impairment in the more recent cohort matches recent epidemiological data, and the difference between the two rates suggests a major difference between the two cohorts (e.g., that the more recent cohort was drawn from a less cognitively impaired population).
Second, on two of the three dimensions measured by the autism diagnostic instrument, the children in the more recent cohort were, on average, less symptomatic than the children from the earlier cohort. The researchers stated that although these differences were statistically significant (i.e., they exceeded the criterion of a statistical test), they were likely not clinically significant (i.e., they were likely not of significance to the clinical presentation); therefore, the researchers suggested that these differences should not be taken as evidence that the diagnostic criteria had broadened. However, refer again to the tallness analogy: Comparing two cohorts of males in McClennan County diagnosed according to our more restricted (74.5-in.) versus our broader (72-in.) criterion would probably result in a statistically significant difference between the two cohorts’ average height—but the difference would be just about an inch (i.e., most likely not a clinically significant difference)."
There's a lot more where that came from but lets jump to this summing up because it is so beautifuly written.
"Epidemics solicit causes; false epidemics solicit false causes. Google autism and epidemic to witness the range of suspected causes of the mythical autism epidemic. Epidemics also connote danger. What message do we send autistic children and adults when we call their increasing number an epidemic? A pandemic? A scourge? Realizing that the increasing prevalence rates are most likely due to noncatastrophic mechanisms, such as purposely broader diagnostic criteria and greater public awareness, should not, however, diminish societal responsibility to support the increasing numbers of individuals being diagnosed with autism. Neither should enthusiasm for scientific inquiry into the variety and extent of human behavioral, neuroanatomical, and genotypic diversity in our population be dampened."
These words I have stolen from US National Library of Medicine, National Institutes of Health 'Three Reasons Not to Believe in an Autism Epidemic'
ulative, as the devices are meant to cooperate and not try to shout over the top of each other. But does that work in practice? Anyway it is interesting to note that Silicon Valley parents are the strictest of all at limiting their own childrens exposure to electromagnetic radiation, set hours for internet access, no taking your tablet or phone into the bedroom. I could say 'do they know something that we dont?' but I just think they are doing what a sensible parent would be doing anyway.
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