UG Aid

As these are difficult to understand and find examples of, i have compiled some info in easiest way i could.  I hope it helps you all :) Hawthorne effect:   the alteration of behaviour by the subjects of a study due to their awareness of being observed. Pygmalion effect:   Investigator inadvertently conveys his high expectations to subjects, who then produce the expected result.  A " self-fulfilling prophecy ". Berkson bias: usually occurs when cases and controls are selected from hospital inpatients.More specifically, when both the exposure and outcome affect the selection and leads to a false negative association.It looks confusing but just look at this example: Consider an investigator studying a relation between diabetes and CHD.He goes to a hospital and gets a list of people admitted with CHD and he selects equal number of controls(inpatients not having CHD). Let us create a 2x2 table here CHD + CHD - Exposure (DM) + a ...

Vaccine requirement is calculated as follows: Total number of pregnant women/infants to be covered × Expected coverage × Number of doses of the vaccine ×Wastage multiplication factor ÷ No. of sessions to be held (or number of doses per vial). No. of pregnant women = Population × Birth rate. No. of infants = Population × Birth Rate × (1-IMR) For Monthly Requirement, divide annual dose by 12. If sessions are held fortnightly, the annual required dose is divided by 24 and if weekly, divide by 52. Expected vaccine coverage=100%=1 Vaccine Dose up to 1 year Doses/Vial Wastage factor TT for pregnant women 2 doses per women 10 doses/vial 1.33 BCG 1 dose per child (at birth) 10 doses/vial 2 OPV 4 dose per child (0,1,2,3) 20 doses/vial 1.33 Pentavalent 3 dose per child (1,2,3) 10 doses/vial 1.33 DPT 3 dose per child (1,2,3) 10 dose...

Confused between confounding and effect modification?? Here is the solution: 1- Confounding bias : Alcohol ( exposure ) Oral cancer ( outcome ) Smoking is a confounding bias here. Why ? Because smoking is related to BOTH the exposure and the outcome. People who smoke will more often than not, also drink, and people who have oral cancer, were probably smokers ( smoking is a known risk factor for oral cancer). 2- Effect modification : OCPs ( exposure ) Breast cancer (outcome ) Family history of breast cancer is an effect modification here. Can you guess why ? Asbestos ( exposure ) Lung cancer(outcome) Smoking is an effect modification Estrogens ( exposure ) DVT (outcome ) Smoking is an effect modification So do you notice the difference ?? The effect modification is ONLY related to the outcome, but NOT to the exposure. Think with me here : smoking does not effect neither asbestos exposure nor estrogen levels or intake,BUT definitely is a risk for lung cancer and DVT !! Family histo...