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| bio | website | |
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| age | ||
| visits | member for | 1 year, 7 months |
| seen | 11 hours ago | |
| stats | profile views | 64 |
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Jan 18 |
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Finding a trend in variance Hi again. Sorry that I'm not explaining it very well. It's not that the variance of any particular variable has a trend. It's the variance of the hospital-level effects (random effects) that has a trend. It is hypothesized that the variation in hospital-level effects has decreased linearly over the period of the data, due to more /consistency/ in clinical diagnosis and treatment (not necessarily /better/ treatment/outcomes, though that is also likely, but not the point). |
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Jan 18 |
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Finding a trend in variance ...Cont... At this point I am searching for published papers, in any field/discipline, where a trend in variance has been modeled at level 1 in a multilevel model. So far I have not found any, but I am pretty sure that there should be some. If anyone can point me in the right direction, or provide links to published research I would be very grateful. |
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Jan 18 |
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Finding a trend in variance Thank you. I'll mark this as the accepted answer soon. First, if you don't mind I'd like to ask a related question which refers to the points @whuber and yourself made. I asked about this because it arose as a consequence of other modelling I am doing. The /real/ problem is described in this open question: stats.stackexchange.com/questions/19911/… It is thought that there has been a near-linear change in randoms effects variance, and that is actually what I'm eventually hoping to model. Cont...... |
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Jan 17 |
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Finding a trend in variance Hi Erik and thanks. You know, I almost posted the question on mapleprimes, not SE ! I ran your code and also got good results, albeit with a "Warning, undefined value encountered" |
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Jan 17 |
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Finding a trend in variance Thank you very much for those suggestions - I will look into them :) |
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Jan 17 |
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Finding a trend in variance Thanks for your comment. It seems to be trivial to you, but it's unwieldy to me and I don't know how to solve such equations in R. |
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Jan 17 |
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Finding a trend in variance Thanks, but I don't know how to do that in R. Wouldn't the likelihood function would be unwieldy with n=1000 ? I fiddled around a little in Maple and didn't have much success there either. |
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Jan 17 |
asked | Finding a trend in variance |
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Jan 16 |
answered | Introduction to structural equation modeling |
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Dec 19 |
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Temporal analysis of variation in random effects Around 100 hospitals, on average around 500 patients per hospital (but of course it's not balanced) |
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Dec 18 |
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Temporal analysis of variation in random effects Thank you. What about using a 3 level hierarchical approach, with patients within years within hospitals. Would this make sense ? |
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Dec 16 |
asked | Temporal analysis of variation in random effects |
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Dec 15 |
awarded | Critic |
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Dec 15 |
awarded | Enthusiast |
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Dec 14 |
accepted | Illustrative datasets and analysis for multilevel modelling |
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Dec 13 |
revised |
Most famous statisticians added url |
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Dec 13 |
awarded | Necromancer |
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Dec 12 |
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Illustrative datasets and analysis for multilevel modelling As for the books in the tag, I have Venables and Ripley (2002) and Gelman & Hill (2006) and haven't found anything there. I also just got Pinheiro & Bates - Mixed Effects Models in S and S-Plus from the library - there are a some pharmacokinetics datasets there, but nothing very close to what I'm looking for. |
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Dec 12 |
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Illustrative datasets and analysis for multilevel modelling Thanks - I have looked at the bristol.ac.uk course and it was quite helpful. However, at this stage I'm really looking for some analysis of patient & hospital data, and unfortunately all their examples (that I saw) were from the social sciences. |
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Dec 12 |
revised |
Illustrative datasets and analysis for multilevel modelling added info about the data I will be working with. |
