Intended for healthcare professionals

Research Methods & Reporting

The tyranny of power: is there a better way to calculate sample size?

BMJ 2009; 339 doi: https://doi.org/10.1136/bmj.b3985 (Published 06 October 2009) Cite this as: BMJ 2009;339:b3985

Article usage

Article metrics provide readers and authors with an indication of how often a specific article has been accessed month by month. It counts three formats - abstract/extract, full text and pdf. The page is updated each day.

Usage statistics: October 2009 to January 2021

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AbstractFullPdf
Oct 2009016890
Nov 200909341
Dec 200902590
Jan 201001760
Feb 201001240
Mar 201001730
Apr 20100970
May 20100790
Jun 20100650
Jul 20100680
Aug 20100490
Sep 201023599
Oct 2010323728
Nov 2010375213
Dec 201037380
Jan 201193540
Feb 201164490
Mar 201147460
Apr 201128340
May 201139560
Jun 201180450
Jul 201187250
Aug 201147460
Sep 201127300
Oct 201139500
Nov 201152340
Dec 201135380
Jan 201230340
Feb 201220410
Mar 201231400
Apr 201238460
May 201228420
Jun 201230320
Jul 201214220
Aug 201227280
Sep 201225240
Oct 201238370
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Jan 201329160
Feb 201327140
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Apr 201332270
May 201330200
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Jul 201323250
Aug 20133740
Sep 20133810
Oct 20131650
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Dec 20130590
Jan 20141920
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Apr 201401600
May 201401490
Jun 201401210
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Aug 201401941
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Oct 201402170
Nov 201413250
Dec 201401850
Jan 201501300
Feb 20150660
Mar 201521201
Apr 20154630
May 20159340
Jun 20153750
Jul 20151390
Aug 20151700
Sep 20157980
Oct 20153630
Nov 201571540
Dec 2015161080
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Feb 201601100
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Apr 201631062
May 201611100
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Jul 20162910
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Mar 201701270
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Jun 201701300
Jul 201701240
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Oct 201701480
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Jan 201801170
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Mar 201821640
Apr 201811220
May 201831190
Jun 20181870
Jul 201851130
Aug 201841580
Sep 20183780
Oct 20181970
Nov 201811170
Dec 201832130
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Feb 201901130
Mar 201901260
Apr 201911190
May 20191940
Jun 20190810
Jul 20191980
Aug 20191930
Sep 20190900
Oct 201901560
Nov 20192920
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Feb 20202900
Mar 202021240
Apr 202011570
May 202042110
Jun 202001050
Jul 202012650
Aug 202042210
Sep 202011530
Oct 2020111720
Nov 202032560
Dec 202001100
Jan 20212690
Total14981639363