The most distinguishing characteristic of the standardized test is the requirement that the instrument be administered to all test takers under the same conditions. These conditions include the directions for administration, which sometimes imposes scripts that must be followed. Other administration conditions include time of year (in the case of achievement tests), time limits, and methods of recording responses. Other features are shared to a greater or lesser degree, such as procedures for developing test specifications, item writing, pretesting items and computing item statistics, and compiling preliminary forms of the tests for field trials.