Randomized control trials (RCTs) randomly assign individuals to experimental and control groups to compare the effect of an intervention. RCTs are blinded, meaning patients, researchers, or data analysts may not know which group received the intervention. This eliminates confounding biases. However, RCTs have limited external validity since volunteers may differ from the general population. They also cannot be used to study exposure to harmful materials.

1. By Dr Aijaz Ahmed Sohag
HOD Com Medicine Dept
Edit by: Abdulwasay Baloch
Amna Inayat Medical College
Randomized Control Trial (RCT)

3. Randomized Control Trial- RCT
 Experiment methods where individuals are randomly allocated
to an experimental or a control group
 The effect or intervention is compare between the two groups
 Two Key Features are:
1. Randomization
2. Controlled
 These trials are BLINDED
 Single blind means the patients do not know what the
intervention is
 Double blind means that netither the patient nor the
researcher knows what the intervention or drug is
 Triple blind means Analysis team also does not know which
is experimental and which is control group

4. Plus Point of the Study
 A unique strength of this study is that it eliminated both
confounding bias both known and unknown

5. Drawbacks of RCT
 External validity refers to extent to which the results can
be generalized to a boarder community
 For RCT , including person is first screened, then only they
are included in trial – this may lead to that volunteers
selected different from those who do not
 RCT cannot be used in instances such as exposure to harm
to harmful materials such as , Toxins, Bacteria