# Thread: Meta-analysis: How to calculate cohen's d using the range of scores and sample size

1. ## Meta-analysis: How to calculate cohen's d using the range of scores and sample size

Hi there,
I am trying to calculate cohen's d (standardised mean difference) for a study that only reports the range (min and max), and not the mean or standard deviation. I am wondering if it's possible to calculate cohen's d using the sample size and range? And if so, what formula will provide the best estimate of d?
Thanks so much,
Dee

2. ## Re: Meta-analysis: How to calculate cohen's d using the range of scores and sample si

Doesn't seem possible to me.

3. ## Re: Meta-analysis: How to calculate cohen's d using the range of scores and sample si

Very roughly sd = (max - min)/4 and mean = (max + min)/2. This may be enough for a rough estimate of Cohen's d, as effect size is a fairly vague measure for a start.
Perhaps this paper could help. Estimating the mean and variance from the median, range, and the size of a sample. Hozo et al
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1097734/

4. ## Re: Meta-analysis: How to calculate cohen's d using the range of scores and sample si

Nice katxt. Haven't read the link yet but I would imagine some assumptions are needed. I wonder if a bunch of simulations could be of use here as well.

I would recommend the standard meta-analysis sensitivity analysis as well, where you run the MA with leave one study out until you have gone through the permutation of included studies.

5. ## Re: Meta-analysis: How to calculate cohen's d using the range of scores and sample si

Thanks so much for your feedback - the reference is incredibly helpful. I will make note to run the sensitivity analysis too.
Thanks again,
d

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