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Calculating caseloads-cmam=SAM/or MAM- need for clarification-part of the formula

This question was posted the Prevention and treatment of severe acute malnutrition forum area and has 15 replies. You can also reply via email – be sure to leave the subject unchanged.

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Cornelia Wakhanu

Normal user

10 Oct 2013, 20:53

From a document found in CMAM Forum on how to calaculate the SAM/ or MAM, The formula is:
Case load = N × P × K × C
N= total population of the under-fives in the catchment area
P=Prevalence rate of the SAM or MAM
K=Correction factor to include the new cases for the specified period of time
C=expected mean program coverage
On the part of K which is calculated by finding:
Incidence factor= (prevalence multiply by t/7.5)
K = Prevalence +incidence factor above
=1+ {1 x(12months/7.5months)}
The twelve months is for one year period. The prevalence is taken as 1,
My question is: time factor change from 12 to lower number like 6 months. This is because some CMAM operation goes for 6 months only not the whole year?
Meaning K =1+1x6months/7.5months=1.8
Or do we still calculate by 12months but go for six months operation per the project plan?
Please anyone who can make me understand this part of formula?

Reference document link:

Thanks, Cornelia Wakhanu

Mark Myatt

Consultant Epideomiologist

Frequent user

11 Oct 2013, 13:44

I think you have it right. With:

    K = 1 + (t / 7.5)

we assume (i) that time is measured in the same units (months in the example you give) and (ii) that the average length of an untreated episode from become a cases to spontaneous cure or death is 7.5 months. That last assumption is based on limited data and some guesswork.

If the period of CMAM operation is 6 months then you would have:

    K = 1 + (6 / 7.5)
    K = 1.8

The key to understanding 'K' is ...

We know we have to treat prevalent cases and we can have some idea of prevalent cases from survey data. There will also be new (incident) cases arising. we will want to treat these too. We want to treat :

    cases to treat = prevalent cases + incident cases

We do not usually have incidence data (a SMART survey (e.g.) yields a prevalence rather than an incidence). We can estimate incidence from prevalence if we have some idea of the duration of an untreated episode. This is (under certain assumptions):
    incidence = prevalence * (period / duration)

So we want to treat :
    cases to treat = prevalence + prevalence * (period / duration)

This can be expressed as:
    cases to treat = prevalence * (1 + period / duration)

The last part of that is our 'K'.

I hope this helps.

Anonymous 2371

Normal user

12 Oct 2013, 11:04

I would like information if you calculate the caseload and you need to plan for the program especially for MAM. Can you have the caseload for MAM as well as estimating the number of OTPs in the planning. Since we do transfer cases of OTP to TSFP. I do I go about it. Can I add the caseload plus the estimates (caseload from OTP) in the planning so as you can have a grand total of beneficiaries for SFP?

Abu Ahammad abdullah

Normal user

13 Oct 2013, 03:47


I think, we can add 75% of the total OTP caseload with estimated TSFP caseload. Considering the below assumption:
1. OTP programme performance is satisfactory
2. Cure rate is above or equal to the sphere standard.
3. Caseload is calculated for OTP based on above formula.

Please let me know, if anyone differ with me.


Anonymous 2371

Normal user

13 Oct 2013, 07:52

Hi All,
Just on the issue of caseload. How do u calculate the caseload of BSFP? Can we use still the prevalence of 5% to calculate the caseload?


Abu Ahammad abdullah

Normal user

13 Oct 2013, 07:59


It is straight forward.

BSFP for U5 children: All 6-59 month children of the catchment area
BSFP for PLW: All PLW of the catchment area.

You don't need to consider the prevalence during calculation of caseload for BSFP.


Cornelia Wakhanu

Normal user

13 Oct 2013, 09:21

Thanks very much Mark Myatt,

Your explanation well understood.


Mark Myatt

Consultant Epideomiologist

Frequent user

13 Oct 2013, 14:02

WRT : "Can you have the caseload for MAM as well as estimating the number of OTPs in the planning" ... A simple approach would be to calculate a GAM caseload using the same "N * P * K * C" approach. A more complicated approach would be to estimate the SAM and MAM caseload separately (this is probably better as you may have different coverage expectations for the two programs). You would then increase MAM workload to account for the OTP cure rate. Something like:

    SFP caseload + (OTP Caseload * OTP Cure rate)

were 'SFP caseload' and 'OTP caseloa'd are calculated from different "N * P * K * C" calculations and 'OTP cure rate' is taken from routine program monitoring statistics might work. You can model these type of questions quite simple simply using a spreadsheet. BTW ... Abu Ahammad Abdullah's response (above) is similar to this and assumes a 75% cure rate (this is the SPHERE minimum standard for OTP cure rate).

WRT "How do u calculate the caseload of BSFP?" ... This can be done in the same way. Don't assume prevalence to be 5%. Use whatever prevalence / disease calendar / food security data you have to make a good guess at prevalence. We can get confused by terms used to describe SFP programs. If by "BSFP" you mean "blanket" SFP and by "blanket" you mean "everyone" (or "everyone 6-59 months and all PLWs") then your caseload is everyone (corrected for expected coverage). Typically this will be all children 6-59 months and all PLWs.

Anonymous 2371

Normal user

13 Oct 2013, 17:43

Thanks a lot. Just to understand we can estimate Blanket SFP based on the information on food security data? and we use the same method of CMAM formula?


Mark Myatt

Consultant Epideomiologist

Frequent user

14 Oct 2013, 07:41

We need to be careful with our use of terms. The term "blanket" usually means "universal" in the sense that all members of the population are eligible to receive the SFP ration. If there is any targeting of the ration (e.g. to poor households, households with a MAM child, women-headed households, &c.) the you have a targeted SFP. I have heard people talk of "targeted blanket SFP". This is a contradictory definition since "targeted" and "blanket" have opposite meanings. Such terms, although they may refer to specific program designs, makes little sense to anyone outside of the emergency nutrition world. They confuse me.

Anyway ... UNICEF have:

Blanket SFPs target a food supplement to all members of a specified at risk group , ... All individuals in a specific group are registered for the blanket SFP. (Module 12 SFP Technical Notes)


Blanket SFPs attempt to prevent a deterioration of the nutritional status of all individuals in a pre-defined vulnerable group ... (Blanket Supplementary Feeding Program Guidance)


These are, in fact, targeted programs. I will (first) assume that you are referring to this type of program.

The caseload calculation is:

    N * P * K * C

The prevalence term 'P' is simple a proportion and correspond to the proportion meeting the targeting criteria. This might be (e.g.) the proportion of households with a MAM child, the proportion of households with a earth floor, &c. depending on your targeting criteria. You would only base this on food security data if you were targeting using food security criteria. Mostly you will use a proxy criteria such as "flooring type" on the basis that poor housing and food insecurity tend to go together. In this example, the term 'P' will be the proportion of hosueholds meeting your proxy criteria.

The prevalence to incidence correction term 'K' might be as used above (e.g. K = t / 7.5) or it might be absent.

The coverage term 'C' is, typically, small for SFPs.

If you are referring to a true "blanket" programs then the caseload calculation simplified to:

   N * C

I hope this helps.

Anonymous 2371

Normal user

14 Oct 2013, 08:40

Hi Mark, I was meaning Blanket supplementary for U2 years and thanks a lot on this.
Kind regards

Mark Myatt

Consultant Epideomiologist

Frequent user

14 Oct 2013, 08:59

For U2 we often mean 6 - 24 or 6 - 23 months. I usually go with 6 - 24 months because mothers often describe (e.g.) a 21 month old child as being two years old and this would lead to an eligible child being excluded. It also swings the other way with (e.g.) a 27 month old child being described as two years old.

Anyway ... the issue for you is defining 'N'. You may have good data on this already. If not then you can use some assumptions and the total population. The assumptions are:

The U5 population is uniformly distributed by age.

The U5 population is about 20% of the total population.

Under these assumptions we have:

    N = Total Population * 0.20 * 18 / 60
    N = Total Population * 0.06

You can drop 'P' or have P = 1 (the same thing). You will have an "incidence" but this will usually be balanced by older children leaving the cohort as younger children join the cohort so 'K' can be ignored or set to K = 1. Your caseload is then:
    Caseload = N * C

Bheru Lal

Nutrition Programme Manager

Normal user

14 Oct 2013, 16:52

Dear All,
I think , it would be helpful for all:

Including incidence, caseload can be calculated as follows:

Caseload = (prevalent cases + incident cases) * coverage

e.g. in a rural population of 200,000 where 20% of children are under 5, GAM is 15%, SAM is 2% and coverage is estimated to be 50% and the proposal funding period is 9 months, the calculation would be:

Stabilisation centre caseload (assuming 15% of SAM cases need inpatient treatment)
= (200,000/100)*20 = 40,000 <5s
= (40,000/100)*0.3 = 120 prevalent cases of SAM with complications (0.3 is 15% of 2% SAM)
= (120*1.6)/12*9 = 144 incident cases of SAM with complications for 9 months
= 144+120 = 264 = incident and prevalent cases for 9 months
= 264/2 = 132 = expected caseload for SC over 9 months with 50% coverage

Outpatient therapeutic programme caseload (assuming 85% of SAM cases can enter outpatient treatment)
= (200,000/100)*20 = 40,000 <5s
= (40,000/100)*1.7 = 680 prevalent cases of SAM without complications (1.7 is 85% of 2% SAM)
= (680*1.6)/12*9 = 816 incident cases of SAM without complications for 9 months
= 816+680 = 1496 = incident and prevalent cases for 9 months
= 1496/2 = 748 = expected caseload for OTP over 9 months with 50% coverage

Supplementary feeding programme caseload
= (200,000/100)*20 = 40,000 <5s
= (40,000/100)*13 = 5200 prevalent cases of MAM (13% is MAM where 2% of GAM is SAM)
= (5200*1.6)/12*9 = 6240 incident cases of MAM for 9 months
= 6240+ 5200 = 11440 = incident and prevalent cases for 9 months
= 11440/2 = 5720 = expected caseload for SFP over 9 months with 50% coverage

126000 U5s

(126,000/100)*18 =22680
(22680*1.6)/12*6 =18144



MAM = 6974



Normal user

17 Jul 2017, 16:18

I am trying to calculate case load of a MAM programme. The total population of the area is 1,008,283; prevalence of MAM is 9%; incidence is 2.6%; coverage of the programme is 50%? Kindly help me calculate case laod for 6 months because am getting some figure below what our programme reached 6 months back. Thanks


Normal user

18 Jul 2017, 06:25

I would advise that you go by your project/programme experience based on the numbers you were able to reach last time you implemented the MAM program .Then work very hard to increase outreach and community mobilization so that you reach as many more children as much as feasible to have a higher coverage than 50%.

Riek Gach

Nutrition project officer (IMC)

Normal user

18 Mar 2018, 12:36

Please can you advise on the formula and how to calculate the answer to this exam question? The exam has already passed but I would like to know it for my experience and my knowledge.

3. According to the SMART Survey results, global acute malnutrition (GAM) is 6.8% and SAM prevalence is 0.9 %. The results of a coverage survey indicated a low coverage of 20% in the ongoing program. In 2012, the number of facilities providing treatment of SAM services increased from to 227 Facilities to 427, whereas national wide the facilities are 1200. In 2013, a total of 32,000 children were admitted to the program with 32,824 cartons of RUTF distributed and several reports of stock outs due to insufficient supplies. The country office is concerned with the higher than expected caseload and RUTF consumption. (20 marks).

a. What is the expected SAM caseload? Using the prevalence and the expected SAM caseload estimated, please calculate the RUTF needed for treatment and explain your calculation.
b. What could be the underlying causes for the high consumption of RUTF? What strategies would you propose to the country office to regulate the consumption of RUTF in-line with the protocol, international standards and expected caseload based on SAM prevalence

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