Multiple Membership Weights

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krcassiday
Posts: 4
Joined: Mon Jan 17, 2022 4:22 pm

Multiple Membership Weights

Post by krcassiday »

Hello! Is it necessary for the multiple membership weights to add up to 1? I have a district-level dataset that includes students in schools. In some cases, students leave the district and are not tracked to the school in which they moved. For example, a student attends an out-of-district school for 4 months and then enters a district school for the remainder of the year. In these cases, the weights won't add up to 1. I was wondering if I needed to include a dummy school to be the "out-of-district" school or if I can just attach a weight to the school attended, even though it would be less than 1. Thanks!
billb
Posts: 157
Joined: Fri May 21, 2010 1:21 pm

Re: Multiple Membership Weights

Post by billb »

Hi,
So there are various schools of thought here. Many people use weights that sum to 1 and I think in my MMMC paper (Browne, Goldstein and Rasbash, 2001) we did that. We have also argued (Tranmer, Steele and Browne, 2014) that it might make sense to make the squares of the weights sum to 1 as then the variance will have the same weight for each observation and might make comparability of the school variance to any other variance easier. It would be possible to put additional (dummy if you like) schools in the dataset though you would have very little information on the schools in question so it would probably be quite shrunk.
Hope that helps,
Bill.
krcassiday
Posts: 4
Joined: Mon Jan 17, 2022 4:22 pm

Re: Multiple Membership Weights

Post by krcassiday »

Thank you so much for your response. I appreciate you providing a few viable options. This information will help me move forward.
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