While researching a topic, a student has taken the following notes:Researchers use randomized controlled trials to test treatment effectiveness. In...
GMAT Expression of Ideas : (Expression) Questions
While researching a topic, a student has taken the following notes:
Researchers use randomized controlled trials to test treatment effectiveness. In this design, participants are randomly assigned to different groups—some receiving the experimental treatment while others receive a control condition.
Dr. Martinez has conducted two such studies. Her 'Mediterranean Diet Study' involved 500 participants who were randomly divided between Mediterranean diet and standard diet groups. Over a two-year period, the research team measured cardiovascular outcomes.
A different study by Dr. Martinez, the 'Low-Sodium Diet Study,' took a similar approach. This research randomly assigned 300 participants into two groups: one following a low-sodium diet and another maintaining their regular diet. Blood pressure changes served as the primary outcome, tracked for one year.
The student wants to use one of the studies to illustrate the randomized controlled trial design. Which choice most effectively uses relevant information from the notes to accomplish this goal?
As a randomized controlled trial, the 'Mediterranean Diet Study' randomly assigned 500 participants to Mediterranean diet and standard diet groups, measuring cardiovascular outcomes over two years to test treatment effectiveness.
Dr. Martinez conducted randomized controlled trials, research designs that test treatment effectiveness through random group assignment, in both the 'Mediterranean Diet Study' and the 'Low-Sodium Diet Study.'
The randomized controlled trial design randomly assigns participants to Mediterranean diet and standard diet groups, which is demonstrated in the 'Low-Sodium Diet Study' with 300 participants.
Dr. Martinez has used randomized controlled trials multiple times, as in the 'Low-Sodium Diet Study,' which assigned 500 participants to measure cardiovascular outcomes over two years.
Step 1: Decode and Map the Passage
Part A: Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| 'Researchers use randomized controlled trials to test treatment effectiveness.' |
|
| 'In this design, participants are randomly assigned to different groups—some receiving the experimental treatment while others receive a control condition.' |
|
| 'Dr. Martinez has conducted two such studies.' |
|
| 'Her 'Mediterranean Diet Study' involved 500 participants who were randomly divided between Mediterranean diet and standard diet groups.' |
|
| 'Over a two-year period, the research team measured cardiovascular outcomes.' |
|
| 'A different study by Dr. Martinez, the 'Low-Sodium Diet Study,' took a similar approach.' |
|
| 'This research randomly assigned 300 participants into two groups: one following a low-sodium diet and another maintaining their regular diet.' |
|
| 'Blood pressure changes served as the primary outcome, tracked for one year.' |
|
Part B: Passage Architecture & Core Elements
Main Point: Researchers use randomized controlled trials to test treatment effectiveness, as demonstrated by Dr. Martinez's two diet studies.
Argument Flow: The passage first defines randomized controlled trials and explains their basic mechanism. It then provides two concrete examples from Dr. Martinez's research to show how this design works in practice, giving specific details about participant numbers, group assignments, and outcome measures.
Step 2: Interpret the Question Precisely
This is a fill-in-the-blank question asking us to choose the best logical connector. The answer must create the right relationship between what comes before and after the blank.
Step 3: Prethink the Answer
To effectively illustrate the randomized controlled trial design, the correct answer should:
- Use accurate, specific details from one of the studies (not vague generalities)
- Show the key elements of RCT design: random assignment, treatment vs control groups, outcome measurement
- Connect these details back to the broader concept of testing treatment effectiveness
As a randomized controlled trial, the 'Mediterranean Diet Study' randomly assigned 500 participants to Mediterranean diet and standard diet groups, measuring cardiovascular outcomes over two years to test treatment effectiveness.
✓ Correct
- Uses the Mediterranean Diet Study with completely accurate details: 500 participants, Mediterranean vs standard diet groups, cardiovascular outcomes, two-year timeframe
- Explicitly identifies it as 'a randomized controlled trial' and connects the specific methods to the broader purpose of testing 'treatment effectiveness'
- Provides the clearest, most complete illustration by combining accurate specifics with conceptual explanation
Dr. Martinez conducted randomized controlled trials, research designs that test treatment effectiveness through random group assignment, in both the 'Mediterranean Diet Study' and the 'Low-Sodium Diet Study.'
✗ Incorrect
- Makes a true but vague statement about Dr. Martinez conducting RCTs in both studies
- Fails to provide any specific details from either study that would actually illustrate how the RCT design works
The randomized controlled trial design randomly assigns participants to Mediterranean diet and standard diet groups, which is demonstrated in the 'Low-Sodium Diet Study' with 300 participants.
✗ Incorrect
- Contains a confusing logical error: claims the Mediterranean Diet Study design is 'demonstrated in the Low-Sodium Diet Study'
- Also gives wrong participant number (300) when discussing Mediterranean diet groups, mixing up details from both studies
Dr. Martinez has used randomized controlled trials multiple times, as in the 'Low-Sodium Diet Study,' which assigned 500 participants to measure cardiovascular outcomes over two years.
✗ Incorrect
- Contains multiple factual errors: gives 500 participants for the Low-Sodium Study (should be 300) and cardiovascular outcomes for that study (should be blood pressure)
- Mixes up details from the two different studies