Are the data analysed according to the original protocol?
If you play coin toss with someone, no matter how far you fall behind, there will come a time when you are one ahead. Most people would agree that to stop the game then would not be a fair way to play. So it is with research. If you make it inevitable that you will (eventually) get an apparently positive result you will also make it inevitable that you will be misleading yourself about the justice of your case. (7) (Terminating an intervention trial prematurely for ethical reasons when subjects in one arm are faring particularly badly is a different matter and is discussed elsewhere. (7)) Raking over your data for “interesting results” (retrospective subgroup analysis) can lead to false conclusions. (8) In an early study on the use of aspirin in preventing stroke, the results showed a significant effect in both sexes combined, and a retrospective subgroup analysis seemed to show that the effect was confined to men. (9) This conclusion led to aspirin being withheld from women for many y
