Frequently Asked Questions


Why was Census written ?

When I first began trying to teach people NONMEM, it became apparent that a console-based application that needed to be compiled on-the-fly was intimidating to people who were used to glorious GUI-based applications like S-PLUS. The output, with all its exponential-format numbers, was especially problematic. Getting the results into a friendly environment and a format that people could read easily seemed the way to go. That, and managing run results was a tedious combination of notebooks and Excel. When you have as many as 500 runs in a project, this becomes a real pain in the neck.

Is Census really open source?

Yes. It is made available under the Mozilla Public License, version 1.1.

Is Census free, then?

Yes. Enjoy.

How is development of Census funded?

It isn't. Census is an entirely voluntary and self-supported project at present. That said, any offers of sponsorship (of software, say) would be very warmly received, and would add a big boost to the further development of the application. Mail me if you'd like to give a starving postdoc a helping hand...

It should be mentioned that the development of Census was previously funded, as part of my PhD research, by the wonderful people at the Division of Pharmacology, in the Department of Medicine at the University of Cape Town. Now that I have graduated, though, that is no longer the case.

Will Census be ported to Linux or Mac format?

If this ever happens, it will need to be substantially rewritten, and I will need to learn Qt4 before starting. So don't hold your breath.

Will Census support NONMEM 7?

Yes. Stay tuned for the very next release...

Will Census support PsN?

Yes. In fact, Census will rely on it in the future.

Does Census support Xpose?


Does Census support R?

Yes. R support is essential to enable Xpose support. 

Will Census support Wings for NONMEM?


Will Census support S-PLUS/PDx-POP?

No. These are commercial products and it is diffcult for freeware developers like myself to use them unless copies are donated. Besides, if you have PDx-POP you probably don't need Census!

Will Census be able to run NONMEM itself?

Yes, once PsN is folded in, NONMEM will have the ability to prepare and execute NONMEM runs as well as interpret them. But not in version 1.x.

If Census breaks my computer or any of my data, or costs me any time or money, or offends me or people or companies that I know in any way, can I sue you?

No. Use at your own risk. It's free, so support is limited, I'm afraid.

Can Census change, delete or damage my run data?

No. Census reads NONMEM input and output, but does not alter it in any way.

Can I cite Census?

Sure! Wilkins JJ. NONMEMory: a run management tool for NONMEM. Comput Methods Programs Biomed. 2005 Jun;78(3):259-67.

Your article calls Census NONMEMory...

Before Census was called Census, it was called NONMEMory. The University of California felt that NONMEMory sounded too similar to NONMEM, and politely asked me to change it. Before NONMEMory, Census was called Drumsticks For NONMEM in an homage to the ground-breaking Wings for NONMEM. Change is the one constant in life...

Can I get support from the University of California or ICON?

Census is a completely independent project, and while it is complementary to NONMEM, has no ties to either UC San Francisco or ICON Development Solutions. Consequently, asking them for support if you have problems with Census will very probably be fruitless. It would be like phoning the power company to tell them that your DVD player's lens needs cleaning.

What did you use to write Census?

Borland Developer Studio 2006 , the Jedi VCL, and a range of open-source components.

I've got BDS! Can I help in the development?

Indeed you may. Download a copy of the source code and get cracking. If you want to help in the mainstream part of the project (this one) rather than starting your own branch, contact me and I'll help you get set up as a project developer at SourceForge.

I haven't got Delphi! Can you give me a copy?

No. You will need to buy a copy from Embarcadero/CodeGear.

Why wasn't Census written in something more widely used than Delphi - like C++, for example?

Good idea, but I started this project as a Delphi developer. One day it would be nice to port Census to Qt, thus making it open source and C++-based, but I will need help... Feel free to volunteer!

Why has Census broken Excel?

Census is innocent. The guilty party is the R(D)COM server - version 2.50 installs a broken plugin into Microsoft Excel and prevents it from loading cleanly("Compile error: Can't find object or library"), most often when trying to open a spreadsheet file by double-clicking it. To solve the problem, make sure you use 2.50 PL1, or, if it has already happened to you, do the following: start Excel from its shortcut in the Start menu, choose Tools -> Add-ins from the menu bar, and deselect RExcel. If this doesn't work for you, or you are experiencing other issues, please contact me.

From version 1.1 of Census onward, R(D)COM is no longer used and this issue will go away.

Why is Census bleating about incompatible versions of Excel? I deselected the plugin!

Again, the R(D)COM server installer is at fault. Messages about incompabile versions of Excel appear if you have Excel 2007, but, while annoying, they are relatively harmless and may be ignored. 

From version 1.1 of Census onward, R(D)COM is no longer used and this issue will go away.

Excel sometimes won't start after I installed Census! "Compile error: Can't find project or library"...

This is an issue with R (D)COM 2.50, which is installed automatically with current versions of Census. It often occurs when double-clicking on spreadsheet files to open them with Microsoft Excel. What has happened is that the add-in that R(D)COM installs into Excel seems to be somewhat buggy. To fix this, start Excel from the Start menu, and uncheck the RExcel option under Tools -> Add-Ins.

From version 1.1 of Census onward, R(D)COM is no longer used and this issue will go away.

Why doesn't Xpose work after I upgraded R to version 2.8.x?

The R(D)COM library rears its increasingly inconvenient head once again. R(D)COM, which is required for Xpose to work in Census versions up to 1.0, itself depends on an R library called rproxy.dll, which has been discontinued from R from version 2.8.0 onwards. Details may be found here. The replacement, rscproxy, is not suitable the purposes of Census.

From version 1.1 of Census onward, R(D)COM is no longer used and this issue will go away.

Why are all the buttons grayed out? I can't do anything!

You need to create a new database for your current modelling project (the first toolbar button) or open an existing one (second button). A database typically consists of several .FF2 files, and ideally should have its own directory. You can, however, put databases in any folder you like as long as there isn't already one there.

I can't see goodness-of-fit plots.

Census uses the same nomenclature as Xpose, in that it expects output data to be arranged into tables with names like sdtab, patab, catab and cotab. To display plots, the sdtab file must be present in the same folder as the model specification file and NONMEM output, and must contain ID, TIME, DV, MDV, EVID, PRED, IPRED, RES and IWRES.

Why do my plots vanish off the page?

Do you have a widescreen display? A fix may be possible. In the meantime, a workaround is to use a display mode with a normal aspect ratio. 

Can I use Census to manipulate my input data files?

This is not planned for now. For models already run, this would be a spectacularly bad idea anyway, for reasons of electronic recordkeeping.

Is Census 21 CFR Part 11 compliant?

No. But it does keep a record of everything that is done (adding, deleting and modifying records) and does not allow key data to be changed.

What are condition numbers and why are they important?

The ratio of the largest eigenvalue to the smallest eigenvalue, referred to as the condition number, is a measure of ill-conditioning. Eigenvalues are generated by NONMEM when the PRINT=E argument is used in the $COVARIANCE record. A condition number exceeding 1 000 is indicative of severe ill-conditioning (Montgomery DC, Peck EA. Introduction to Linear Regression Analysis. Wiley, NY, 1982, pp. 301-302). Thanks to William Bachman for this definition, which I've shamelessly stolen.

What about shrinkage?


And conditional weighted residuals (CWRES)?


Great, but I also need visual predictive checks (VPCs)...

Further down the line.

The Census icon appears to be a chicken. Why is this?

When I first started learning NONMEM, back in the dim and dusty past (2001), it was on a DOS platform, using Nick Holford's Wings for NONMEM as a frontend. When development first started on Census, it was called Drumsticks for NONMEM to reference what had come before. The icon stuck. The name didn't.

Will there be more frequently asked questions?

Yes indeed. Just as soon as I find the time to write them down, and just as soon as I get asked them more than once.


Last update: 4-Jan-2011