Because of the hierarchy of research designs, a true experiment will always have higher internal validity than a quasi-experiment.

A researcher conducts a true experiment on the effects of sleep on memory but fails to control for participants studying at different times of day, uses inconsistent instructions across conditions, and does not standardize the testing environment. Meanwhile, a colleague uses a quasi-experimental design comparing morning-shift and night-shift workers on alertness, carefully matching groups on age, health, and caffeine use, and holding all other procedures constant. Which statement best explains the relative internal validity of these two studies?