How do i determine the sample size for a study looking at the treatment outcomes of mental health patients in a community house that is a step down from inpatient unit.
The study will look at outcome measures from when participants first enter the house as well as at discharge(up to 14 days) and at 3 months(after community follow-up).
It will also look at the client satisfaction survey results completed at these time frames.
We will be using a convenience sample.
Currently there are 8 people in the houses at a time.
Also if anyone knows, how would you determine if someone is too unwell and should be excluded from the study. Most patients are fairly stable in the house but require additional support prior to discharge to the community. Ive read a number of studies but no one clearly defines how they make that decision.
Thank you for taking the time to help
Kind regards Margaret
Dear Campbell
Determining sample size is a very important issue because samples that are too large may waste time, resources and money, while samples that are too small may lead to inaccurate results. In many cases, we can easily determine the minimum sample size needed to estimate a process parameter, such as the population mean.
If the population is known (sample size calculation with finite population) then you can use any of the following calculators to know the sample size.
1. https://www.surveysystem.com/sscalc.htm
2. https://www.calculator.net/sample-size-calculator.html
3. https://apps.who.int/iris/handle/10665/40062
I mostly used the following online calculator:
4. https://select-statistics.co.uk/calculators/sample-size-calculator-population-proportion/
Some related research paper available on researchgate:
1. Article Sample Size Determination in Health Studies: A Practical Manual.
2. Article Sample size calculation
When You have not any idea about the population ( here in your question i.e. the prevalence of any disease) so you need to use the sample size calculation with a non-finite population. (As per your nature of question)
And in this case,(sample size calculation with non-finite population) you go with the Cochran formula, for this please follow the link:
https://www.statisticshowto.com/probability-and-statistics/find-sample-size/
or you can visit any other link related to Cochran formula (Sorry I do not know how to type the formula here, so please go to any of the link or just search):
1. https://www.researchgate.net/post/Is_that_possible_to_use_Cochran_formula_sample_size_determination_for_heterogeneous_groups_populations
2. https://gist.github.com/marcoscaceres/7137166
Some pages related to "determine the sample size from an unknown population" is on researchgate with the following links:
1. https://www.researchgate.net/post/How_can_we_determine_the_sample_size_from_an_unknown_population
2. https://www.researchgate.net/post/How_do_I_determine_sample_size_for_each_strata_in_survey2
And if the you are conducting case study then the size of sample doesn't matter.
Please find some of the files (related to sample size calculation) as attached files.
Hope you find all the information useful in the way to determine sample size as the case you have.
Happy researching...
Thank you so much Subhash Chandra Basu I will read all the material you send through. Thanks for taking the time to help me with this. Margaret
SAMPLE SIZE METHODOLOGY. A good summary in one table of various sample size methods is provided in the link below:
http://sphweb.bumc.bu.edu/otlt/MPH-Modules/BS/BS704_Power/BS704_Power_print.html
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