+ Reply to Thread
Results 1 to 9 of 9

Thread: Is univariate analysis a must before binary logistic regression

  1. #1
    Points: 373, Level: 7
    Level completed: 46%, Points required for next Level: 27

    Posts
    11
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Is univariate analysis a must before binary logistic regression




    Could I enter all my independent variables directly for a binary logistic regression

    OR
    is it necessary that I should run a one way anova for each of the independent variables first and select only the significant ones for the binary logistic regression with the dependant variable

    Please help

  2. #2
    TS Contributor
    Points: 12,501, Level: 73
    Level completed: 13%, Points required for next Level: 349

    Posts
    951
    Thanks
    0
    Thanked 103 Times in 100 Posts

    Re: Is univariate analysis a must before binary logistic regression

    You don't need to do univariate analysis first.

    One thing to note is that even if a variable is not significant in univariate analysis, it may still have a place in a logistic regression.

    Quote Originally Posted by jm_manipadam View Post
    is it necessary that I should run a one way anova for each of the independent variables first and select only the significant ones for the binary logistic regression with the dependant variable
    FYI there are issues with throwing in all the significant ones.

    Just be reasonable in how many variables you put into your regression.
    All things are known because we want to believe in them.

  3. #3
    Omega Contributor
    Points: 38,253, Level: 100
    Level completed: 0%, Points required for next Level: 0
    hlsmith's Avatar
    Location
    Not Ames, IA
    Posts
    6,989
    Thanks
    397
    Thanked 1,185 Times in 1,146 Posts

    Re: Is univariate analysis a must before binary logistic regression

    Univariate analyses may also miss interaction relationships.
    Stop cowardice, ban guns!

  4. #4
    Points: 373, Level: 7
    Level completed: 46%, Points required for next Level: 27

    Posts
    11
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Re: Is univariate analysis a must before binary logistic regression

    Thanks a lot☺

  5. #5
    Points: 373, Level: 7
    Level completed: 46%, Points required for next Level: 27

    Posts
    11
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Re: Is univariate analysis a must before binary logistic regression

    Quote Originally Posted by Mean Joe View Post
    You don't need to do univariate analysis first.

    One thing to note is that even if a variable is not significant in univariate analysis, it may still have a place in a logistic regression.



    FYI there are issues with throwing in all the significant ones.

    Just be reasonable in how many variables you put into your regression.
    What would be the maximum number of variables that we could put in the regression. My study has eight variables

  6. #6
    TS Contributor
    Points: 40,089, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Awards:
    Downloads
    gianmarco's Avatar
    Location
    Italy
    Posts
    1,367
    Thanks
    232
    Thanked 301 Times in 225 Posts

    Re: Is univariate analysis a must before binary logistic regression

    Quote Originally Posted by Mean Joe View Post
    You don't need to do univariate analysis first.

    One thing to note is that even if a variable is not significant in univariate analysis, it may still have a place in a logistic regression.

    I agree with you. Yet, I am struck by the quantity of academic works (e.g., PhD dissertations) in which the inclusion of predictors into regression (either, linear, logistic, ect) is based on the univariate analysis on each single predictor against the DV. I have seen this, for example, in more than a couple of PhD dissertations from a famous University in Europe.

    Gm
    http://cainarchaeology.weebly.com/

  7. #7
    TS Contributor
    Points: 40,089, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Awards:
    Downloads
    gianmarco's Avatar
    Location
    Italy
    Posts
    1,367
    Thanks
    232
    Thanked 301 Times in 225 Posts

    Re: Is univariate analysis a must before binary logistic regression

    In my logistic regression modelling, I have followed this:

    Peduzzi et al, "A simulation study of the number of events per variable in logistic regression analysis" (https://www.ncbi.nlm.nih.gov/pubmed/8970487)

    The minumum number of observations should be:
    N = 10 k / p
    where p be the smallest of the proportions of negative or positive cases, and k the number of covariates
    http://cainarchaeology.weebly.com/

  8. #8
    Omega Contributor
    Points: 38,253, Level: 100
    Level completed: 0%, Points required for next Level: 0
    hlsmith's Avatar
    Location
    Not Ames, IA
    Posts
    6,989
    Thanks
    397
    Thanked 1,185 Times in 1,146 Posts

    Re: Is univariate analysis a must before binary logistic regression

    I think the unvariate analysis component may get propagated due to two reasons:

    -historically before big computing, it was probablyly easier to run a bunch of uni's then multiple regression;

    -experimental studies will check covariate balance between the two treatment groups, I bet many believe this is a form of doing a bunch of uni's, which it is actually something different.
    Stop cowardice, ban guns!

  9. #9
    Points: 373, Level: 7
    Level completed: 46%, Points required for next Level: 27

    Posts
    11
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Re: Is univariate analysis a must before binary logistic regression


    Has this univariate first come as a part of purposeful selection of variables from a whole lot of variables. But I saw in one tutorial that they use p <0.25 to select those variables from univariate for multivariate. So out of my eight variables with a sample of 310 should I do this purposeful selection and can I use p value of less than 0.25 or should I enter all variables?

+ Reply to Thread

           




Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts






Advertise on Talk Stats