Intended for healthcare professionals

Rapid response to:

Endgames Statistical Question

What is recall bias?

BMJ 2012; 344 doi: https://doi.org/10.1136/bmj.e3519 (Published 23 May 2012) Cite this as: BMJ 2012;344:e3519

Rapid Response:

Re: What is recall bias?

You say: "However, women who slept on their back or

on their right side on the previous night (before

stillbirth or interview) had more than twice the risk

of a late stillbirth compared with women who slept on

their left side." But Stacey et al, the authors you

quote, give as their results:
"...(adjusted odds ratio for back sleeping 2.54 (95%

CI 1.04 to 6.18), and for right side sleeping 1.74

(0.98 to 3.01))."
By convention, if the odds ratio includes 1.0 then

the result is not significant. So right side sleeping

had no effect in this study.

J.R. Johnstone PhD
7 Bruce St,
Nedlands 6009,
Western Australia

08 9386 7080
0408 990 936
ray@iinet.com.au
www.iinet.com.au/~ray

Competing interests: No competing interests

27 May 2012
Jeffrey R. Johnstone
retired
none
none
7 Bruce St, Nedlands 6009, Western Australia