Final answer:
To control order effects in a repeated measures design, one should use counterbalance.
Step-by-step explanation:
To control order effects in a repeated measures design, one should use counterbalance. Counterbalancing involves systematically varying the order of treatments within a group of participants to eliminate any potential bias caused by the order of presentation. By counterbalancing, each treatment is presented in a different order for different participants, ensuring that any effects observed are not due to the order of treatments.