In contrast to achievement tests, diagnostic tests are designed to analyze individual performance and identify special disabilities. Most of these tests are concerned with reading, but a few have to do with mathematical skills. The reading tests range from group tests for rapid but superficial checking to individual tests of an intensive clinical nature. The latter usually provide detailed check lists of errors, and frequently utilize a tachis- toscope, ophthalmoscope, or other apparatus. The following are representative samples of both types of tests:Iowa Silent Reading Tests. This short, widely used group test consists of an elementary battery (grades 4-8) and an advanced battery for high school and college. Both cover rate of reading, vocabulary, sentence comprehension, paragraph comprehension, use of an index, as well as a test of “directed reading” in which the subject identifies parts of a paragraph that answer given questions.Nelson-Denny Reading Test. A test for high school, college, and adult groups, yielding separate scores on vocabulary, reading comprehension, and reading rate, with norms based on a large nationwide sample.Diagnostic Reading Tests. A more intensive series, for grades 7-13, containing (a) a survey section for an entire class, testing vocabulary and ability to read and comprehend story and textbook material; and (b) a diagnostic battery from which tests can be selected according to difficulties revealed on the survey test. This battery measures vocabulary from various subjects, comprehension of textbook material (silent and auditory), rate of reading of different types of material, and word attack, both oral and silent.Durrell Analysis of Reading Difficulty, for grades 1-6. Designed for intensive individual testing, this battery measures rate and comprehension of oral and silent reading, word and letter recognition, word pronunciation, with supplementary tests of written spelling and speed of handwriting. It also includes tests for non-readers on visual memory, rate of learning words, and learning comprehension. A check list is provided, based on reading errors gathered from a study of 4000 children.Other diagnostic reading tests are: the Gates-McKillop Reading Diagnostic Tests (grades 1 to 8), the Gilmore Oral Reading Test (grades 1 to 8), the Group Diagnostic Aptitude and Achievement Test (grades 3 to 9), the Roswell- Chall Diagnostic Reading Test (grades 2 to 6), and the Diagnostic Reading Scales. The most recent instrument is the Stanford Diagnostic Reading Test (1967), a reliable group test for grades 2.5 to 4.5 and grades 4.5 to 8.5. This test was standardized on over 12,000 students in six school systems, and yields separate scores on such skills as comprehension, vocabulary, blending, syllabication, sound discrimination and, in the later grades, rate of reading.The Compass Diagnostic Test in Arithmetic is a comprehensive group test for grades 2 to 8, consisting of twenty subjects covering different types of arithmetic operations and problems. The Diagnostic Chart for Fundamental Processes in Arithmetic, for grades 2 to 8, is an example of a thorough test for individual administration. Since the problems have to be solved orally, the examiner can observe not only errors but methods of attack. A checklist of errors and faulty work habits is included. No time limits, no norms or total scores are given, since the test is designed for qualitative rather than quantitative analysis. Two other important tests in this area are the Diagnostic Tests and Self-Helps in Arithmetic and the new Stanford Diagnostic Arithmetic Test (1967) which, like the Stanford Diagnostic Reading Test, is available in two equivalent forms, at Level I (grades 2.5 to 4.5) and Level II (grades 4.5 to 8.5).