The Systematic Differences Between the Control and Treatment Groups Can

question 15

Multiple Choice

The systematic differences between the control and treatment groups can be controlled by taking two years data, _____.​

• A)​one treatment group before policy change and one after the change
• B)​one before the policy change and one after the change
• C)one control group and one treatment group
• D)​one control group before policy change and one after the change