Question

In which of the following cases is a measure considered reliable?

		The Balance Tracking System (BTrackS) force-plate captures the center of pressure (a measure of postural control) of an older adult in an experimental session of 3 trials with consistent results
		A new motion capture system software had highly variable results measuring angular velocity of the elbow joint in 2 trials under similar conditions
		A measuring tape essential for measuring the distance required to accurately place a marker 4 feet away from the starting point, stretched out about half an inch under the sun
		None of the above measures are considered reliable

Sources of variability in an experimental study can be minimized by:

		Using written instructions
		Repeating the experimental trials and taking the average of these trials per participant
		Avoiding testing all study participants on the same day
		All of the above can be used to minimize sources of variability in an experimental study

Answer 1

1)

Option A ie The Balance Tracking System (BTrackS) force-plate captures the center of pressure (a measure of postural control) of an older adult in an experimental session of 3 trials with consistent results

Variation in measurements can be avoided by:

• Using clearly defined diagnostic criteria
• Observing participants under similar biological/environmental conditions
• Training observers
• Blinding observers and participants to the study hypothesis
• Using calibrated, easy-to-use equipment
• Employing standardised measurement methods
• Piloting questionnaires to identify ambiguous questions

2)

Option A ie Using written instructions or Using clearly defined diagnostic criteria