Dear Elrofaay,

Can you clarify about the settlement setup? As it is refugee setting, Is there updated Household listing?

Dear Elrofaay:

I am a bit confused by your inquiry. In general, an active case search is incompatible with a representative sample of the population. Presumably, the objective of an active case search is to identify all cases in a population, not to use a sample of the population to generalize findings to the larger population. Therefore, there is no sample size for an active case search.

Dear Elrofaay:

I am a bit confused by your inquiry. In general, an active case search is incompatible with a representative sample of the population. Presumably, the objective of an active case search is to identify all cases in a population, not to use a sample of the population to generalize findings to the larger population. Therefore, there is no sample size for an active case search.

I agree with Bradley's opinion. For active case finding, a sample is not needed. However, if you want to estimate the prevalence/rate of cases..., a sample is needed. If so, more information is needed to know which sample size calculation method is needed. For example, the sample size calculation formula may be different depending on whether you want to conduct a cross-sectional or cohort/longitudinal study.

For the sampling technique, simple or systematic random sampling can be used once you have the list of the study population (here the refugees). You may need to stratify or create clusters depending on the interest of a discriminating factor in the sample or if the camp is too large.

With a little more detail, you will be able to have more information.

Dear Sir, 

For your intervention in refugee camp, better seek for the last reported cases.I can imagine with such level of household to screen you should move step by step particular when we don't have enough funds.

1st  Last distribution of Guinea worn in the camp.            

2nd Choose the most affected area to apply door by door your case definition (Community based one or a particular one you have)

3rd Depending on level of funds applied to all  households the definition by moving from most prevalent area to less affected.

But if you don't have   enough fund to cover all your targeted households, think about reducing the number of households you desire to screen with active case intervention.

In such intervention do not forget we are working on maximizing our chance to detect existing cases household after household. There is no need of sampling:" We eat all the cow, not one portion"

Best wishes

The enquiry is unclear; this leads to assumptions; let's assume the two scenarios. 

Scenario 1: If the need is how to calculate/estimate the target for the implementation of the project, then, consideration of the previous prevalence, and incidence rate with plan for the duration of the project (number of months/year) can help to estimate the target population.  This can be adopted from any public health planning approach to address the needs.

Scenario 2: If the need is to search for general prevalence in the refugee population point in time,  then calculating a representative sample for an assessment is advisable. In the camp/settlement simple random method is recommended, usually, the settlement pattern (structure) is convenient and data are available for the purpose. Note: Seasonal/time factors always affect the interpretation of the findings. 

Finally, I would recommend contacting the team operating in the camp, they usually have experience conducting various studies and assessments in the camps. 

Best regards

Samuel T.