Stanine
Encyclopedia
Stanine is a method of scaling test scores on a nine-point standard scale with a mean
of five and a standard deviation
of two.
Some web sources attribute stanines to the U.S. Army Air Forces
during World War II
. Psychometric legend has it that a 0-9 scale was used because of the compactness of recording the score as a single digit but Thorndike claims that by reducing scores to just nine values, stanines "reduce the tendancy to try to interpret small score differences (p. 131)". The earliest known use of Stanines was by the U.S. Army Air Forces in 1943.
Test scores are scaled to stanine scores using the following algorithm:
The underlying basis for obtaining stanines is that a normal distribution is divided into nine intervals, each of which has a width of 0.5 standard deviations excluding the first and last. The mean lies at the centre of the fifth interval.
Stanines can be used to convert any test score into a single digit number. This was valuable when paper punch cards were the standard method of storing this kind of information. However, because all stanines are integers, two scores in a single stanine are sometimes further apart than two scores in adjacent stanines. This reduces their value.
Today stanines are mostly used in educational assessment. The University of Alberta
in Edmonton
, Canada
used the stanine system until 2003, when it switched to a 4-point scale http://www.registrar.ualberta.ca/ro.cfm?id=184. In the United States, the Educational Records Bureau (they administer the "ERBs") reports test scores as stanines and percentiles.
Mean
In statistics, mean has two related meanings:* the arithmetic mean .* the expected value of a random variable, which is also called the population mean....
of five and a standard deviation
Standard deviation
Standard deviation is a widely used measure of variability or diversity used in statistics and probability theory. It shows how much variation or "dispersion" there is from the average...
of two.
Some web sources attribute stanines to the U.S. Army Air Forces
United States Army Air Forces
The United States Army Air Forces was the military aviation arm of the United States of America during and immediately after World War II, and the direct predecessor of the United States Air Force....
during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. Psychometric legend has it that a 0-9 scale was used because of the compactness of recording the score as a single digit but Thorndike claims that by reducing scores to just nine values, stanines "reduce the tendancy to try to interpret small score differences (p. 131)". The earliest known use of Stanines was by the U.S. Army Air Forces in 1943.
Test scores are scaled to stanine scores using the following algorithm:
- Rank results from lowest to highest
- Give the lowest 4% a stanine of 1, the next 7% a stanine of 2, etc., according to the following table:
| Result Ranking | 4% | 7% | 12% | 17% | 20% | 17% | 12% | 7% | 4% |
| Stanine | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
The underlying basis for obtaining stanines is that a normal distribution is divided into nine intervals, each of which has a width of 0.5 standard deviations excluding the first and last. The mean lies at the centre of the fifth interval.
Stanines can be used to convert any test score into a single digit number. This was valuable when paper punch cards were the standard method of storing this kind of information. However, because all stanines are integers, two scores in a single stanine are sometimes further apart than two scores in adjacent stanines. This reduces their value.
Today stanines are mostly used in educational assessment. The University of Alberta
University of Alberta
The University of Alberta is a public research university located in Edmonton, Alberta, Canada. Founded in 1908 by Alexander Cameron Rutherford, the first premier of Alberta and Henry Marshall Tory, its first president, it is widely recognized as one of the best universities in Canada...
in Edmonton
Edmonton
Edmonton is the capital of the Canadian province of Alberta and is the province's second-largest city. Edmonton is located on the North Saskatchewan River and is the centre of the Edmonton Capital Region, which is surrounded by the central region of the province.The city and its census...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
used the stanine system until 2003, when it switched to a 4-point scale http://www.registrar.ualberta.ca/ro.cfm?id=184. In the United States, the Educational Records Bureau (they administer the "ERBs") reports test scores as stanines and percentiles.