Our data suggest substantial variability, often with over 25% of rates being in upper tail.
For persons in discrete core studies, 55 different studies provided 170 rates. The median value for rates was 15.2 per 100,000. The distribution was positively skewed. Excluding the top and lower 10% of the distribution, rates ranged from 7.7 to 43.0 per 100,000 (a five-fold difference). Because schizophrenia has a relatively low level of prevalence, zero provides an absolute 'floor' for the rate distribution. NB while the lower tails of the distributions were usually data-sparse, many of the distributions had upper tails that contained more than 25% of the rates. Several of the distributions had marked positive skewness. Thus deviation is predominantly for higher rather than lower estimates.