[SMARTKeymaster]

Hello,

There are several parameters you need to calculate sample size (estimated prevalence, desired precision, design effect for cluster surveys, average household size, proportion of children under 5, non-response rate, size of total population if small and level of confidence). Assuming you’re referring specifically to estimated prevalence/death rate that need significant consideration, continue reading below.

When calculating sample size, the Estimated Prevalence for the indicator of interest should be as close as possible to what you think the real prevalence will be.

1) If there is no previous information about the prevalence of your main indicator in the target population, gather all available information about the indicator of interest in the country/region. Look at different sources such as surveys in similar area/context and season, for example:

Previous survey in neighbouring areas
Surveillance data including proportions of children visiting clinics with malnutrition
Program staff from MoH, UNICEF, etc.
National demographic data.
MICS or DHS survey data done in the past or neighbouring district
Passive screening data from permanent health centre sites
Health workers, religious leaders

2) Consider how the prevalence has changed since the existing information was collected (has the situation deteriorated/improved?). Do not use previous survey results blindly without adjusting for differences between then and now. Justify your decision using contextual data such as:

Aggravating factors
Seasonality
Implementation of nutrition/feeding
Crises
Food security
Population movement

3) Determine the range of plausible values of prevalence and use the higher number (closer to 50%) to be conservative and achieve an acceptable precision.

Increasing your estimate of prevalence (closer to 50%) will increase your sample size. Similarly for mortality sample size calculation, estimate the crude death rate accessing available information to determine a range and choose the higher end to be conservative. Be careful not to grossly overestimate.

SMART Team

• This reply was modified 9 years, 12 months ago by  SMART.
• This reply was modified 9 years, 12 months ago by  SMART.

[SMARTKeymaster]

Thank you for checking that you are using the updated version. It would be great to find out if your colleagues are having the same problem with their computers/ENA software.

Please send us your dataset to info@smartmethodology.com and our programmers can take a closer look.

[SMARTKeymaster]

Please check that the version of ENA you are using is most recent – July 9, 2015 version is available for download on our site here https://smartmethodology.org/survey-planning-tools/smart-emergency-nutrition-assessment/

Please advise if the problem persists.

[SMARTKeymaster]

If lists are not available after segmentation, most often lists can be built. It’s important that segments are manageable to household level. Administrative units should be accessed to request additional information required to build lists.

Please refer to SENS Guidelines for information on surveying mixed populations of resident and migrant populations.

• This reply was modified 10 years, 1 month ago by  SMART.

[SMARTKeymaster]

Number of clusters = total number of households in the sample/number of households one team is able to visit per day

In order to determine the number of clusters in a survey, you must determine the number of households a team can feasibly visit in one day.

However, in the event surveyors are prevented from accessing previously selected clusters after survey starts (for unforeseen circumstances), ENA automatically chooses additional clusters called reserve clusters or replacement cluster (RC).

Please note, only use RC when 10% or more of the original number of clusters were impossible to reach OR final sample size is less than 80% of the required number.

Example
If your target is to survey 40 clusters, but:
A. You could only access 38 clusters (5% missing), you do not use the RC.
B. You could only access 36 clusters (10% missing), you should include all RC in your survey, even there are 5 of them.

• This reply was modified 10 years, 2 months ago by  SMART.

[SMARTKeymaster]

ENA has limited capacity to analyze additional variables. To compensate for this, the CDC created one software package that combines ENA and Epi Info to make analysis of additional variables collected as easy and reliable as possible. Read more about the software package and download for free here: https://smartmethodology.org/survey-planning-tools/smart-emergency-nutrition-assessment/combination-epi-info-ena-software/

[SMARTKeymaster]

The plausibility check assigns SMART flags on data points that are +-3 Z-scores from MEAN OF SURVEY POPULATION (i.e. the observed mean) and NOT from reference mean. This is to compare each child within its own population that was surveyed, thus SMART flags range will be different in each sample/survey.

Example
Q. If we did a survey and the mean weight for height Z-score of the survey is -0.8, what would be the range for SMART flags?
A. Lower [-3 + -0.8 = -3.8] and upper [+3 + -0.8 = +2.2] range of SMART flags. Any children that fall below or above these limits (-3.8, +2.2) will be ‘flagged’ and excluded from the analysis. WHZ flags are in bold in the plausibility check.

[SMARTKeymaster]

Hi Harshal and Blessing,

Thank you for bringing this to our attention. It appears there was a glitch with a link on the website. It is now fixed and the new version of ENA is now available for download at smartmethodology.org.

Thanks for your patience on this issue.

[SMARTKeymaster]

Hi Dr Naren Patil,

Thank you for your question. In the most recent version, we have made the following changes:

1) Correction in the plausibility report for anthropometry: Chi-squared test for comparison of age groups (6-29 vs. 30-59 months) is integrated into the summary table of the plausibility report and replaces the overall age distribution test.
2) A survey protocol template feature has been introducted. You can click on the MS Word button under the “Planning” tab to generate a survey protocol template, which includes a basic outline of what you need to plan your survey including a table of parameters for sample size calculation.
3) Mortality surveys: Additional information is now provided in the results for mortality surveys (e.g., # of HHs, birth rate, % U5 children, etc.).
4) Spanish has been added as an additional language option in ENA. To change languages, access the menu under Extras > Other Languages.

[SMARTKeymaster]

There is a new version of ENA from April 21, 2015 available on the SMART website.

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