با همکاری:/ایدز، دانشگاه علوم HIVمرکز منطقه ای آموزش نظام مراقبت

پزشکی کرماناداره ایدز و بیماریهای آمیزشی، مرکز مدیریت بیماریها

مجری برنامه:دانشگاه علوم پزشکی آذربایجان شرقی

/ایدز، برآورد HIVکارگاه پیشرفته کشوری نسل دوم نظام مراقبت جمعیت و روشهای نمونه گیری در جمعیت های سخت در دسترس –

1390 آبان 5 تا 1تبریز

روشهای مستقیم تخمین جمعیت

علی اکبر حقدوست، اپیدمیولوژیست

Direct methods

Counting members of a target sub-population by direct contacting or direct observing

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Direct size estimation methods

1. Survey: Large scale cross-sectional study by selecting a random sample from the whole population

2. Census: counting all individuals of interest

3. Enumeration: counting a proportion of individuals of interest

4. Snowball technique (nomination method)

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Survey

• Household survey is the best possible option but– It is prone to selection bias (absent groups)– It is prone to information bias– It is very difficult to implement because of the

required sample size and logistics

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Census

• Based on mapping, this method requires visiting every place of interest and counting members of the target population

• It needs– High quality map– Well-trained researchers to know subjects– Executing the study in a brief period of time to avoid

duplications (migrations)

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Enumeration

• Enumeration method also focuses on counting individuals of interest

• Based on mapping, a number of locations are chosen; members of a hidden population will be counted only on these chosen locations

• The obtained number is then multiplied according to the size and structure of the sampling frame (provided by mapping)

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Snowball approach

• A snowball-like (chain referral) method of identifying members of the target population; the size of population size has an association with the concept of saturation; but it has its own limitations such as– Double counting– Networking pattern– Mathematical computations

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