Hello Everyone,
I am working in cancer- case control study and I find difficultis in calculationg samples size. This is becasue we do not have an exact population number and we do not have cancer registry. I just can not find any way to calculate the sample size. Can any one help me with this?
The best information on this is Chapter 7 in Statistical Methods in Cancer Research vol II
Breslow and Day IARC 1987.p 272-314
there are also many on line calculators on the web (Google)
a simple one I have used for unmatched case control studies is at ;
www.stat.ubc-ca/~rollin/stats/size/caco.html
Dear Mona,
I use the program "ene 3.0" is very complete for differents types of study. I hope that I can help you.
Kind regards,
I agree with James Leigh that the IARC book is good. The chapter is at:
http://www.iarc.fr/en/publications/pdfs-online/stat/sp82/SP82_vol2-7.pdf
However, I read your question differently (I apologize if wrong):
Most sample size calculations have to base estimates of some of the numbers needed on not much more than a best guess. I would say that a lot of confidence in doing this right comes from getting over the unpleasant feeling of having to make a best guess when you are used to base things on actual data. Moreover, quite those guesses are adjusted when the resulting sample size does not seem right, e.g. because funding is clearly not going to be sufficient for the required sample size when using conservative guesses.
Hope this helps, again I apologize if I misunderstood your question.
you can try DSS research website its very easy to use .here is the link
https://www.dssresearch.com/KnowledgeCenter/toolkitcalculators/samplesizecalculators.aspx
Sample size calculation for case control study depends to a large extent on the study population size, nature of the case being studied whether it is a commonly seen case or a rare case . i have come across several formula for calculating sample size, review some literature to guide their application.
I use online Openepi calculator. Of course with a number of assumptions . This has always helped me
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