

How many customer development interviews is enough? - mfishbein
http://mfishbein.com/how-many-customer-development-interviews/

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mswen
Some good advice in this blog post.

I remember a conversation with Bill Wells about customer research. Key points
he made:

Keep doing qualitative interviews and focus group until you aren't hearing new
stories/needs/pains - now you have documented the range of related issues and
are starting to have a sense of which customer issues are most common.

If you have the time and money use the qualitative research to guide the
design of quantitative research that will help you understand the scope and
extent of the various issues.

Use statistical analysis but use it carefully and remember that there is not a
cliff at p< 0.05, also just because something is statistically significant
doesn't mean it is of practical significance. Always ask the "So what?"
question of any research findings.

