▪An entry is left blank when a value is required.

▪A numeric value or code falls outside a range that is defined by a minimum and maximum value, or does not exist among the listed responses. For example, if a scale has keycode values from 1 to 5, an entry of 6 is not valid because it exceeds the maximum allowed value.

▪A numeric value or code is entered with insufficient digits. For example, if a numeric entry is required to be 2 digits in length, an entry of 1 is not valid; an entry of 01 would be valid.

▪A numeric value or code is entered with a decimal or fraction when it should be a whole number.

▪An alpha or other character is keyed when a numeric value is required (or vice-versa).

▪Duplicate values are entered for the same multiple response variable.

▪A date is entered that falls outside of the range of defined dates. For example, if a valid date range is April 1, 2009 at 12:00am through April 7, 2009 at 11:59pm, then an entry of March 30, 2009 would not be valid because it is too early for the defined range.