Comparability
The response categories changed over time. From 1988-1990, sample persons were asked to what extent they believed the statement to be true, ranging from "definitely true" to "definitely false". Starting in 1991, sample persons were asked only if they believed the statement to be true or false.
Changes in survey design (e.g., quarters in which the supplement was collected) may affect raw frequencies, but do not affect comparability of the variable. As always, data users should use the prescribed IHIS weights.
