CMM software support FAQs

If you already own a copy of MLwiN and have not upgraded to the latest version, please upgrade to MLwiN for free as this may solve some problems.

Other sources of help

• Try our MLwiN user forum where we welcome all users to post enquiries
• You can also join the Multilevel Modelling discussion list
• If you have bought MLwiN, you may be entitled to email support. (You are entitled to free email technical support if you have bought MLwiN or MLn (exceptthe PhD version)
  • Note: If you are a UK academic and have downloaded the free version you are not entitled to free support.
• Resources for using MLwiN
• Our online course with its practical instructions for using MLwiN and other software

FAQs

• Downloading MLwiN
• MLwiN 2.1/beta/trial/other versions
• Realcom
• MLwiN and operating systems
• Getting data in and out of MLwiN
• Large datasets
• Worksheets
• Sample size, significance testing and suitability of data
• Errors and crashes: Error messages during estimation/ implausible results
• Errors and crashes: crashes/problems opening MLwiN or worksheets
• Errors and crashes: Other errors/problems
• How do I…? Categorical variables
• How do I…? Commands and macros
• How do I…? Discrete response models
• How do I…? Longitudinal data
• How do I…? MCMC
• How do I…? Missing data
• How do I…? Parameters and parameter estimates
• How do I…? Partitioning variance and the intra-cluster correlation
• How do I…? Residuals
• How do I…? Standard errors
• How do I…? Using weights
• Miscellaneous

Downloading MLwiN

• For all questions about downloading and purchasing MLwiN please go to Ordering MLwiN FAQS
  • e.g: my MLwiN download does not work

(Back to top)

MLwiN 2.1/beta/trial/other versions

• Should I uninstall the MLwiN 2.10 beta version I have before installing a later version?
• I already have MLwiN 2.10 beta but the upgrade to the latest version will not work
• What is the difference between the training, the trial version and the full version?
• Can I open SPSS/Stata/Minitab worksheets using the training version of MLwiN?

Realcom

• Does multiple imputation in Realcom work with the free trial version of MLwiN?
• Other problems with Realcom or Realcom-Impute

MLwiN and operating systems

• What are the MLwiN system requirements?
• Can I install MLwiN onto a Mac or Linux system?
• Is MLwiN compatible with Microsoft Vista?
• Is MLwiN compatible with Windows Vista, Server, x64 Edition, MCE and Multi-core/Multi-processor environments?
• Is it possible to run MLwiN on a Citrix-desktop?

(Back to top)

Getting data in and out of MLwiN

• How do I get data into MLwiN?
• How do I get data out of MLwiN?
• Are there any issues I should be aware of when opening my Stata/SPSS/Minitab files with MLwiN 2.1?
• Opening a .dta (Stata) worksheet, I get the error message 'Duplicate name(RSTA)'
• I'm trying to export a number of variables from MLwiN, but only the first 5 appear in the text file

Large datasets

• How do I know MLwiN can handle the model based on my own data?
• I'm having problems importing a large dataset from SAS
• I'm having problems working with a large dataset in MLwiN. Does MLwiN have a limit to the size of dataset that it can handle?

Worksheets

• How do I increase the worksheet size?
• Does each row correspond to a single record right across the MLwiN worksheet?
• Does it matter what order the data appears in in the worksheet?
• Other questions about worksheets

(Back to top)

Sample size, significance testing and suitability of data

• Sample sizes for Multilevel Models
• MLPowSim
• Sample size, significance testing and suitability of data
  • How can I calculate confidence intervals in MLwiN?
  • What significance tests for both random and fixed parameters are available in MLwiN?
  • How do I test whether two coefficients are equal?
  • How do I test whether more than 2 coefficients are equal?
  • How do I test if an interaction between a continuous and a categorical variable is significant?

Errors and crashes: Error messages during estimation/ implausible results

Go to Errors and crashes >>

• I get an error message when I run my model/ numerical problems
• I got an error message 'cannot allocate rmatrix(ws)(like)'
• I tried to run a binomial model and got an error message
• I tried to run a binomial model and got an error message (2)
• When do I allow negative variances?
• I get an error message 'wrong parameter…' when using MCMC
• When I get the error message "MCMC error 0315: prior variance matrix is not positive definitive" while running a multinomial model using MCMC, what exactly do I need to do to the numbers in C1096?
• I get an error message asking me to 'generate unique ID codes'. How do I do this?
• Implausible results or convergence problems
• MLwiN is giving the standard errors of parameter estimates as 0, but I know from comparison with other software packages that the standard errors should not be 0

Errors and crashes: crashes/problems opening MLwiN or worksheets

• Why has MLwiN crashed?
• The European convention of using a comma as a decimal point causes MLwiN 2.10 Beta to crash when using the Intervals and Tests window
• MLwiN fails to open after changing the default worksheet settings
• When I run MLwiN I get the error message "Pre or Post file does not exist (post)"
• I have a worksheet saved on a network drive that I can't open using MLwiN
• When I try to open the worksheets for the LEMMA course I get an error message
• When I double click on one of the worksheets for the LEMMA course, it opens with notepad not MLwiN

(Back to top)

Errors and crashes: Other errors/problems

• When trying to plot a graph, I get the error message 'Failed to open Graphics Server'
• Why has my data become corrupted?
• I can't get the LOGOn command to work
• I noticed a difference in values I get between versions of MLwiN
• Other errors/problems

How do I…? Categorical variables

• How do I update the category labels for a categorical variable?
• I've recoded a categorical variable, but the list of category codes I see when I press Categories has not been updated
• How do I get rid of an unneeded dummy variable/ response category?
• Other questions about categorical variables

How do I…? Commands and macros

• How can I easily save and run commands?
• When I work with MLwiN using the various windows, is there any way to record the commands that will do the same thing?
• I copied commands generated by MLwiN when I was using the GUI and pasted them into a macro, but when I ran the macro I got an error message
• Output from my macro is not appearing in the Output window
• Can I run my old macros written in MLn under MLwiN?
• Will macros written for version 2.02 work with earlier versions of MLwiN?
• I’d like to call MLwiN from the command line. Is that possible?
• Other questions about commands and macros

(Back to top)

How do I…? Discrete response models

• How can I specify a binomial response model using a macro?
• What is the command for specifying the denominator when fitting a binomial or multinomial model?
• Why is the log-likelihood value not displayed in the Equation Window when a Binomial or Poisson model has been fitted?
• MLwiN gives different results to SAS and Stata
• How do I calculate variance functions for multinomial models?
• How do I interpret the estimates for the fixed part parameters in a Poisson model?
• Other questions about discrete response models

How do I…? Longitudinal data

• Does MLwiN need repeated measures data to be in long or in wide format?
• Is it possible to define an AR process for the random effects at level 1?
• When should I allow level 1 errors to be autocorrelated?
• Where are the time series macros?

How do I…? MCMC

• Can I change the length of the burn-in without re-running the model?
• Running MCMC from a macro doesn't appear to work

(Back to top)

How do I…? Missing data

• How do I explore the patterns of missingness in my data? (PDF, 381kB).
  This document shows how you can produce a list of all the patterns of missingness in your data together with information on how frequently each one occurs.

How do I…? Parameters and parameter estimates

• Where is the model fitting information stored in MLwiN?
• Is it possible to output the error variance-covariance matrices for parameters?
• Is it possible to constrain parameters in MLwiN?
• How can I constrain random parameters to zero?
• How can I constrain fixed parameters to zero?
• How can I constrain parameters to values other than zero?
• How can I constrain two parameters to be equal?
• Other questions about parameters

How do I…? Partitioning variance and the intra-cluster correlation

• Partitioning variation across levels - more information
• Where can I find the random parameter matrix in MLwiN? How do I use this to work out the residual ('unexplained') variance at each level?
• How do I calculate the amount of variation at each level for nonlinear models?
• What is the intra cluster correlation?

How do I…? Residuals

• My residuals column is too short
• Should the comparative SD output when I calculate the residuals be different for each row?
• Residuals slide presentation with voice-over plus transcript

(Back to top)

How do I…? Standard errors

• Sandwich estimators for standard errors - more information
• Can MLwiN produce robust standard errors?
• Other questions about standard errors

How do I…? Using weights

• What are weights and how do I use them?
• Is the weights facility in MLwiN still experimental?
• Differential weightings - more information
• How do I use weights in a multiple membership model?

Miscellaneous

• My Names window looks different to the screenshots in the training materials and I can't find all the buttons mentioned in the instructions
• Is it possible to fit splines in MLwiN?
• Does each row correspond to a single record right across the MLwiN worksheet?
• My level 2 variables are being treated as level 1 variables
• MLwiN can no longer PRINT windows

(Back to top)