Stanine (STAndard NINE) is a method of scaling test scores on a nine-point standard scale with a
mean
There are several kinds of mean in mathematics, especially in statistics. Each mean serves to summarize a given group of data, often to better understand the overall value ( magnitude and sign) of a given data set.
For a data set, the '' ar ...
of five and a
standard deviation
In statistics, the standard deviation is a measure of the amount of variation or dispersion of a set of values. A low standard deviation indicates that the values tend to be close to the mean (also called the expected value) of the set, whil ...
of two.
Some web sources attribute stanines to the
U.S. Army Air Forces
The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and ''de facto'' aerial warfare service branch of the United States during and immediately after World War ...
during
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...
. Psychometric legend has it that a 1–9 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 tendency 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.
Calculation
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:
The underlying basis for obtaining stanines is that a
normal distribution
In statistics, a normal distribution or Gaussian distribution is a type of continuous probability distribution for a real-valued random variable. The general form of its probability density function is
:
f(x) = \frac e^
The parameter \mu ...
is divided into nine intervals, each of which has a width of 0.5 standard deviations excluding the first and last, which are just the remainder (the tails of the distribution). The mean lies at the centre of the fifth interval.
Use today
Today stanines are mostly used in educational assessment.
* The
University of Alberta
The University of Alberta, also known as U of A or UAlberta, is a Public university, public research university located in Edmonton, Alberta, Canada. It was founded in 1908 by Alexander Cameron Rutherford,"A Gentleman of Strathcona – Alexande ...
in
Edmonton, Alberta
Edmonton ( ) is the capital city of the Canadian province of Alberta. Edmonton is situated on the North Saskatchewan River and is the centre of the Edmonton Metropolitan Region, which is surrounded by Alberta's central region. The city anch ...
, Canada used the stanine system until 2003, when it switched to a 4-point scale.
* In the United States, the
Educational Records Bureau
Educational Records Bureau (ERB) is an educational services Non-profit Organization that offers assessments for both admission and achievement for independent and selective public schools for Pre K-grade 12.
ERB was founded in 1927, and is h ...
(they administer the "ERBs") reports test scores as stanines and percentiles.
* The
New Zealand Council for Educational Research uses stanines.
* GL Assessment use stanines alongside SAS (Standardised Age Scores) to express the results of its CAT4 assessments, used in many UK and British international schools
"GL Assessment"
/ref>
* The Otis-Lennon School Ability Test uses a stanine system along with percentiles.
* Average Korean High School uses stanine system to evaluate their students
* The IDF (Israeli Defense Force) uses the stanine grading system ranging from 10 to 90 (10,20,30 and so on) to rank intelligence ability relevant to the army's use, determined by a 100 question test divided to 4 categories having to do with different uses and implications of cognitive abilities
See also
* Sten scores – a similar system, but with 10 possible values
* Normal score The term normal score is used with two different meanings in statistics. One of them relates to creating a single value which can be treated as if it had arisen from a standard normal distribution (zero mean, unit variance). The second one relates t ...
Notes
References
* Ballew, Pa
Origins of some arithmetic terms-2
. Retrieved Dec. 26, 2004.
* Boydsten, Robert E. (February 27, 2000)
Volume Six
MEN AND PLANES
THE ARMY AIR FORCES
In World War II
PREPARED UNDER THE EDITORSHIP OF
WESLEY FRANK CRAVEN
JAMES LEA GATE
Princeton University
University of Chicago
Here is a link to the document:
http://www.afhso.af.mil/shared/media/document/AFD-101105-019.pdf {{Webarchive, url=https://web.archive.org/web/20161123154009/http://www.afhso.af.mil/shared/media/document/AFD-101105-019.pdf , date=2016-11-23
Educational assessment and evaluation
Scales
Comparison of assessments
Psychometrics