Steps in conducting a RCT 1. Drawing up a protocol 2. Selecting Reference & Experimental population 3. Randomization 4. Manipulation or Intervention 5. Follow up 6. Assessment of outcome 1. Drawing up a protocol Aims and objectives of the study Questions to be answered Criteria for the selection of study and control groups Size of the sample & allocation of subjects in both groups Treatment to be applied - when, where, how Standardization of working procedures and Schedules as well as responsibilities of persons involved in the trial up to the stage of evaluation of outcome of the study. 2. Selecting Reference and Experimental Populations Reference or target population - Population to which the findings of the trial, if found successful, are expected to be applicable (Eg: drugs, vaccines, etc.) Experimental or Study population Derived from the Reference population Has same characteristics as the Reference population Actual population that participates in the experimental study Must give informed consent - Should be qualified or eligible for the trial 3. Randomization Heart of the control trial Procedure: Participants are allocated into study and control groups Eliminates bias and allows comparability By random allocation every individual gets an equal chance for being allocated in to either groups. 4. Manipulation/ Intervention Having formed the study and control group, the next step is to intervene or manipulate the study (experimental) group by deliberate application or withdrawal or reduction of a suspected causal factor Eg: Drug, Vaccine, Dietary component, a habit 5. Follow up Implies examination of the experimental and control group subjects at defined intervals of time in a standard manner, with equal intensity, under the same given circumstances in the same time frame till final assessment of outcome. Attrition: Inevitable losses to follow up (death, migration, loss of interest) 6. Assessment a. Positive results: Reduced incidence or severity of disease Reduced cost to health service Appropriate outcome in the study b. Negative results: Increased severity or frequency of side effects Complications Deaths BIAS: Any systematic error in the determination of association and outcome. Bias may arise from errors of assessment of outcome due to human element Subjective bias Observer bias Evaluation bias 1. Subjective Bias: Participants, subjectively feel better or report improvement if they knew they were receiving a new form of treatment. This is known as “Subject variation”. 2. Observer Bias: Investigator measuring the outcome of a therapeutic trial may be influenced if he knows beforehand the particular procedure or therapy to which the patient has been subjected. 3. Evaluation Bias: Investigator may subconsciously give a favorable report of the outcome of the trial. Blinding: 1. Single Blind Trial: Participant 2. Double Blind: Partcipant + Investigator 3. Triple Blind: Participant + Investigator + Data Analyzer