When all participants receive all treatment conditions, the study is susceptible to

When all participants receive all treatment conditions, the study is susceptible to (a) Order effects

(b) Carryover effects

(c) Analysis of covariance

(d) a and b

✅ Correct option: (d) a and b

Explanation:

When participants experience all treatment conditions, as in within-subjects designs, order effects (practice or fatigue) and carryover effects (residual influence of previous treatment) may occur. Counterbalancing is used to control these threats.

10 Related PPSC Facts:

Within-subject designs use same participants. Order effects influence outcomes. Carryover affects subsequent treatments. Counterbalancing reduces bias. Latin square controls order. Practice improves performance. Fatigue reduces accuracy. Washout periods reduce carryover. Repeated measures increase power. Random order improves validity.