Poisson and negative binomial regression SPSS (June 2023)

In this video, I provide details on how to generate and interpret results from both Poisson and Negative binomial regression models (both of which are used when the dependent variable is a low frequency count outcome).
You can download a copy of the dataset used in the video here:
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Download a copy of the Powerpoint referenced in the video here:
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Download Excel file here:
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Video on zero-inflated Poisson and negative binomial regression using SPSS: • Zero inflated Poisson ...
Check out other videos and resources at: sites.google.c...

[@moryu7390]

Thank you so much for posting, your videos are an absolute life saver!!

[@mikecrowson2462]

You are so welcome!

[@user-yh6rd2xf6g]

Practical and informative illustration ! Thank you so much.

[@geertvandamme544]

First of all: thanks and congrats for a great video!
1 kind comment:
When putting categorical variables in the Factor box, you can actually 'flip' the reference group to the first one, via the "options" button. This solves your issue and is more in line with theory.

[@mikecrowson2462]

Thank you so much for your feedback! Yes, you are correct. Believe it or not, I've used that option before, but I failed to remember using it when I was putting this video together. I really do appreciate you visiting and taking time to comment! Best wishes!

[@hosammoubarak7007]

Very informative as usual.

[@adele_Tian]

Thank you so much!!!!!!!!! Very useful!!!!!!!!!

[@mikecrowson2462]

You are very welcome!

[@gauravigawade]

So helpful. Thank you so much!

[@abreham2010]

It is such a helpful lecture. When there is under dispersion, can you suggest how to do it in SPSS?

[@mikecrowson2462]

Hello there. Thank you for visiting! After doing a bit of looking online (there does not appear to be much discussion on the issue of underdispersion; most is concerned with overdispersion), I found a posting by Joseph Hilbe (see stats.stackexchange.com/questions/67385/what-is-the-appropriate-model-for-underdispersed-count-data), who recommended hurdle model or generalized Poisson regression. Neither of these options are available in SPSS unfortunately. I found this (journals.sagepub.com/doi/pdf/10.1177/1536867X1201200412) article online that refers to a an approach with Stata where you may be able to use generalized Poisson regression. It is worth mentioning that the authors of that article suggest that with underdispersion, standard errors tend to be overestimated. Logically, the effect would be deflated test statistics and loss of power. An option (if you are assuming underdispersion) when running your model using SPSS is to adopt a more liberal alpha level to offset loss of power that might arise as a result of underdispersion. However, that presumes you have correctly identified a problem with underdispersion; and liberalizing alpha might not be something reviewers would necessarily accept. I hope this helps!

[@bsahab]

Thank you so much for these valuable videos!! Can we use Poisson regression to estimate for example the annual prevalence rate of a binomial outcome through out a 10-year period while adjusting for factor variables?

[@dyoolyoos]

This is a great video, thank you! Can I use NBR or Poisson regression in analyzing count data from a longitudinal dataset with one entity, say the number of weekly deaths from a disease as the outcome variable (and some mix of continuous and factor variables as predictors)?

[@heizehua5661]

Hello, but how do we do quasi poisson?

[@user-bs2ht8iv6y]

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[@user-uu4vw8ut8d]

Very informative and useful video! However the dependent variable boosted my anxiety 🥲 haha just joke

[@jesangelidias6091]

Thank you so much! So helpful.