RE: Clinically meaningful4 Oct 2019 17:19
Your analysis is misleading. First, the datum at 9 months, as has been pointed out already, is a single point, not a mean. For that reason I would exclude it as unreliable. Using the rest of the data (while conceding we cannot do the ideal, repeated-measures analysis of variance on the data as presented) it's possible do to a rough-and-ready regression and correlation analysis of mean increase versus time since treatment (ie the rest of the data in your table) ...... which gives an indication that the relationship between time and improvement is highly significant with 92% of the variance explained and that each additional month since treatment adds about 3 more letters of improvement. If you add the 9-month observation into the mix, obviously the strength of the effect declines but, as I said before, it's not really possible to weight the analysis properly for sample size given the information we have. My judgement is that the 9 months point, given the strong relationship shown by the rest of the data (linear and not showing any sign of peaking, by the way), is an outlier and should be included only when other 9-month points are available. In summary, the data so far gives me confidence this works and I would expect to see a mean value for the 9-month datas, once more samples are in, of about 37 letters. Let's hope so.