Referring Back to Question 10, How Did the Outcomes of Precision

Referring back to question 10, how did the outcomes of precision, range, and rank-ordered matching differ?
The three matching procedures differed in how well they controlled group weight: precision matching (mean difference = 0), range matching (mean difference = 1 pound), and rank-ordered matching (mean difference = 3.5 pounds).They also differed in the number of pairs formed: precision matching (3), range matching (7), and rank-ordered matching (8).
What are the pros and cons of using each procedure?
Precision matching provides the best control over an extraneous subject variable since group scores are identical (pro), but discards the most data (con).
Range matching allows an experimenter to balance control over an extraneous subject variable against the number of scores discarded (pro), but usually discards more scores than rank-ordered matching (con).