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Discrepancy between EpiInfo 2000/ENA and ENA for SMART

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Anonymous 81

Public Health Nutritionist

Normal user

6 May 2010, 13:53

Question regarding the discrepancy between Epi info and SMART was posted in this forum and the detail answer was given by Mark Myat, Michael Golden, and Kevin Sullivan. My question is with specific to EpiInfo/ENA and ENA for SMART that are developed by the same initiative. The Initial ENA/EPIinfo is still available on public on the following website http://www.nutrisurvey.de/ena_beta/ena-epiinfo/index.htm
Very recently ENA for SMART which has the Food security, MUAC and improved mortality is released on http://www.nutrisurvey.de/ena_delta/index.htm under version ena_delta.exe My assumption was that they produce the same result as both product was built from the same source and designed by the same people. However, I found that they are producing different anthropometric result. My question is which one to use in the context of SMART perspective? I have checked whether it is due to setting of minimum and maximum index but both are the same i.e SMART setting (WHZ -3.0 to +3.0, HAZ -3.0 to +3.0, WAZ -3.0 to +3.0), and EPI info setting (WHZ -5.0 to +5.0, HAZ -6.0 to +6.0, WAZ -6.0 to +5.0).
Thanks

Juergen Erhardt

Normal user

7 May 2010, 22:23

As the one who is programming the ENA software I should have been earlier responding to the questions on this website. Sorry that I was not aware of these discussions.

If there should be any problem with the software please send a description and if possible the source data to my e-mail address (erhardtj@gmail.com). Then it is very easy to solve the problem and to post it also on this website. If there are problems they are mostly caused by different settings or misunderstanding the functionality of the program.

For the confusion with the different versions the basic problem is that we try to improve things and then it's very difficult to avoid that improved results create confusion. In general the newest version should be the best for the functionality, but to be on the safe side it could be better to use the older versions since they are longer in use and better tested. Therefore we have still three versions on the website www.nutrisurvey.net/ena_beta (approved version from Oct 2007, beta version from Nov 2008 and the most recent delta version from May 2010).

For the development of a Mac version the problem is that we have very limited resources and therefore to focus on the most used operating system. Since it is easy to run a Windows software like ENA on a Mac I hope it is not too problematic.

For the MUAC the delta version of ENA (www.nutrisurvey.net/ena_delta) should contain now the essential things (some plausibility checks, calculating prevalence rates with changeable cut off's including cluster adjusted confidence intervals, MUAC z-scores for the new WHO standards). This is relatively new and we are glad for any feedback.


Mark Myatt

Consultant Epideomiologist

Frequent user

6 May 2010, 14:16

I am writing in ignorance as I do not use this software (no Mac versions) ... but ... you should check those exclusion / flagging criteria. I think the SMART method uses the sample mean and SD (i.e. all cases 3 SDs below the survey mean are excluded) and EpiInfo uses the reference mean and SD (i.e. all cases below - 5 Z are excluded). Just an idea.

Anonymous 81

Public Health Nutritionist

Normal user

6 May 2010, 16:22

Dear Mark,

Thanks for your response. I have checked by using the same exclusion/flag criteria in both still shows difference.

Anonymous 108

Nutritionist

Normal user

6 May 2010, 19:18

i also agree that these softwares do different things like producing a different graphs each time you click or close and open, the same happens to results and is really confusing in addition to having three versions of the softwares,we are getting confused and need to some help on which version to use

Mara Nyawo

Nutrition Specialist / UNICEF

Normal user

6 May 2010, 20:55

I agree - I would like to know which version (of the ENA for SMART software) is officially approved for use by programme staff in the field? Is the latetst delta version likely to still contain bugs? And is there any news as to when the up-dated version of the SMART Manual will be released? Thanks.

Mark Myatt

Consultant Epideomiologist

Frequent user

7 May 2010, 11:10

Anonymous 108,

Can you clarify what you mean ... is is that the same software with the same data gives different results? Or ... is it different software with the same data give different results? Or ... both of these.

It might be useful if you could describe the differences a little bit.

Also, check that the different software are handling oedema in the same way.

Kevin Sullivan

Normal user

7 May 2010, 15:59

Concerning this issue, a couple of things:
* Epi Info for Windows provides anthropometric calculations for the "old" WHO references (CDC/NCHS 1978) and the US reference (2000).
* ENA provides anthropometric calculations for the old WHO reference and the new WHO reference (2005)
* Note that WHO has software to perform the anthropometric calculations on the old and new WHO reference (http://www.who.int/childgrowth/software/en/)

Are the differences at the individual level or aggregate level?
* To compare the individual level, calculate the z-scores in Epi Info and also using ENA - compare the z-scores for each individual. There may be some minor differences depending on the mathematical accuracy of the computing program at the 2nd decimal place. If there are major differences here, please notify the Epi Info and ENA groups
* If the individual z-scores are the same but the aggregate estimates differ, e.g., mean, percentage <-2SD, then it could be the exclusion criteria. Epi Info provides all z-scores, it is up to the user to exclude these from the analysis, either using the "flag" variable or making their own criteria. I am not sure how ENA does this.

Hope this helps.

Mark Myatt

Consultant Epideomiologist

Frequent user

8 May 2010, 12:22

The lack of Mac and Linux versions of these applications is a side issue. I use Macs and am not greatly inconvenienced by the lack of a native versions of these applications because I have my own software for calculating nutritional indices.

I feel compelled to comment ... there are plenty of cross-platform development environments that can produce software that runs on all platforms. For the SQUEAC method we use (and will be developing further) a program called xMind. This is written in Java under the Eclipse framework. We also use BayesSQUEAC which is written in TCL/TK. Both of these applications run on Windows, UNIX, Linux, and Mac OS X. It is not very much more expensive to develop cross-platform software then to develop for Windows.

Oh ... and xMind and BayesSQUEAC are open source software ... they can be maintained and developed using free tools.

Just my tuppence.

Anonymous 81

Public Health Nutritionist

Normal user

8 May 2010, 19:00


Reply to Kevin
I have checked all individual records generated by EpiInfo/ENA and ENA for SMART. There is no difference in individual Z-scores result. The different is during analysis of all subjects (aggregation). I have checked four survey results. The difference was seen in two of them but in the other two it is the same.

Juergen Erhardt

Normal user

8 May 2010, 21:09

Since there are several options to analyze data it can easily happen that results between the two programs are different. When it is possible for you to send me the data and the different results (to erhardtj@gmail.com) I can easily find out why this happened and post the explanation here.

Ranjith

Normal user

30 Oct 2010, 16:51

I was just wondering if the data finally get analysed by the SMART software programmer and what was identified as the reason for discrepancy...

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