Prior to computing quantiles the simulation was standardized by subtracting the median and dividing by the interquartile range and similarly for the data.
The median number of participants per trial in the sample of 258 reviews was 118 (interquartile range, 60 to 241).
The number of databases searched per review ranged between 1 and 27 (mean, 5.5; median, 4; interquartile range from 3 to 6).
Most outcome scores were non-normally distributed therefore outcome measures were described in median scores, including interquartile range.
Most participants reported having injected drugs for many years (median 17 years, range 1-51, interquartile range 9-25).
The finding is substantively identical if one substitutes the median and interquartile range for the mean score plus or minus one standard deviation.
The median age was 31 years (interquartile range 27-34 years).
The total number of sources used per review ranged between 2 and 30 (mean 8, median 6; interquartile range from 5 to 9).
