Interesting and it helps me understand this better than most resources on this. But I still don't really understand how purposive sampling differs from clearly defining your study population. You say you have to think about which groups you will be sampling - but is this not just setting out inclusion criteria? Clear inclusion criteria set out the population of interest and then you sample using convenience sampling, or quota sampling etc. Purposive sampling is a term I dislike as it implies there are non-purposive samples, sampling to no purpose - and who would do that?
ivan gee Dear Ivan, You are right that probability or non-probability sampling methods imply both defining the population of interest. However a random sample will let the (final) selection of each sample to chance... this is where it differs from a purposive sampling, where the selection process is not pending on the probability to fall or not within the sample. In the humanitarian field we have this pretty well defined with the humanitarian profile (feel free to send an email to info@acaps.org and we will send you an example of humanitarian profile from Nepal). The basic assumption is that each of those group will be affected in a different way.it is more likely that IDPs in public building will need more of food and NFI than IDPs in host communities. Hence, a field assessment will target specially those groups and repeat assessment of a same unit of analysis until no novelty emerge from interviews. I agree a non purposive sample doesn’t make sense, but I have never heard this expression before. I hope this helps. Again if you need more info, please send us an email at info@acaps.org. Bets wishes, Patrice, ACAPS Head of Analysis
Professor...im studying how effective a particular model of professional development is. Thus my sample will include those are doing that PD. Would tbat be considered purposive sampling?
Dear Professor, If we want collect data from the people who have experience with Facebook. We use filtering questions and ask them, Do you have experience with Facebook? If yes, please answer the questionnaire. Do you call it purposive or convenience sampling? Form my opinion, it is convenience sampling as I just conveniently collected data and later based on filtering question will remove the one that has no experience with Facebook.
Yes, this is a convenience sample as you are taking whomever comes to you. It would be purposive if you went after certain types of people, and you could do that on Facebook. In that case it would become both purposive, and convenience….. My Best, Richard
Thank you, Professor Garfield. It is just what I needed
Thank you so much professor. This makes it more understandable to me.
Thanks a lot for sharing. It is very useful and more understandable.
It is really very much useful professor. I understood it well.
so useful! thanks prof. wish me luck on my undergraduate thesis defense about refugee women in indonesian
Perfect, very helpful. Thank you so much for posting it
Great demonstration, thanks.
Thank you, great illustration
very specific, thank you!
Interesting and it helps me understand this better than most resources on this. But I still don't really understand how purposive sampling differs from clearly defining your study population. You say you have to think about which groups you will be sampling - but is this not just setting out inclusion criteria? Clear inclusion criteria set out the population of interest and then you sample using convenience sampling, or quota sampling etc. Purposive sampling is a term I dislike as it implies there are non-purposive samples, sampling to no purpose - and who would do that?
ivan gee
Dear Ivan,
You are right that probability or non-probability sampling methods imply both defining the population of interest. However a random sample will let the (final) selection of each sample to chance... this is where it differs from a purposive sampling, where the selection process is not pending on the probability to fall or not within the sample.
In the humanitarian field we have this pretty well defined with the humanitarian profile (feel free to send an email to info@acaps.org and we will send you an example of humanitarian profile from Nepal). The basic assumption is that each of those group will be affected in a different way.it is more likely that IDPs in public building will need more of food and NFI than IDPs in host communities. Hence, a field assessment will target specially those groups and repeat assessment of a same unit of analysis until no novelty emerge from interviews.
I agree a non purposive sample doesn’t make sense, but I have never heard this expression before.
I hope this helps. Again if you need more info, please send us an email at info@acaps.org.
Bets wishes,
Patrice, ACAPS Head of Analysis
Professor...im studying how effective a particular model of professional development is. Thus my sample will include those are doing that PD. Would tbat be considered purposive sampling?
Dear Professor, If we want collect data from the people who have experience with Facebook. We use filtering questions and ask them, Do you have experience with Facebook? If yes, please answer the questionnaire. Do you call it purposive or convenience sampling? Form my opinion, it is convenience sampling as I just conveniently collected data and later based on filtering question will remove the one that has no experience with Facebook.
Yes, this is a convenience sample as you are taking whomever comes to you. It would be purposive if you went after certain types of people, and you could do that on Facebook. In that case it would become both purposive, and convenience…..
My Best,
Richard