What does a “significant difference” between treatments mean?

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  • Format Audio, Texts
  • Language/s English
  • Target Audience Self-directed learning
  • EBM Stage 3 - Appraising evidence, 4 - Decision making
  • Difficulty Introductory

Key Concepts addressed


What does a “significant difference” between treatments mean?


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Robert42 16:22pm Fri 07 Mar 2014

The wording here is not inaccurate but it is unfortunate. Saying that a statistically significant result is unlikely to have occurred by chance implies causality of the treatment being tested. That isn't true. A statistically significant difference is simply one where the measurement system (including sample size, measurement scale, etc.) was capable of detecting a difference (with a defined level of reliability). Just because a difference is detectable, doesn't make it important, or unlikely.

Douglas_Badenoch 17:30pm Fri 07 Mar 2014

@Douglas_Badenoch Hi Robert Thanks for your comment, and important clarification. I think here the authors made a trade-off between precision and getting the message across. There is a similar comment on the previous page (hit Previous above to see it), to which Paul Glasziou, one of the co-authors, gave a reply which is much better than any I could hope to muster. Please check it out and do let us know if you feel it merits further discussion. cheers Douglas

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