# Thread: Calculating sample size with adequate power to validate a scale?

1. ## Calculating sample size with adequate power to validate a scale?

Hello All,

I am having some difficulty trying to calculate the power and to also determine an adequate sample size for a study looking to determine the the construct, convergent and divergent validity of a scale survey. I came across a research paper by Anthione et al "Sample size used to validate a scale: a review of publications on newly-developed patient reported outcomes measures" and unfortunately they also did not provide any specific methods.

We have 110 initial items in our survey to be administered to n=250 participants to examine the survey's psychometric properties. In particular, I need to justify why n=250 has adequate power given we have 110 items in our survey. Any comments will be appreciated!

Cheers!

2. ## Re: Calculating sample size with adequate power to validate a scale?

Why? n=250 is not necessarily a sufficient sample size... The exact calculations would depend on the test you are running. Why did you mention "Anthione et al "? Is your honest expectation is us reading the paper, instead of having you take your time to describe the test?... Cheers.

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