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JACS

JACS (the Joint Academic Coding System) is a way of classifying academic subjects and modules.

Note: A new subject coding system - the Higher Education Classification of Subjects (HECoS) - has been developed to replace the JACS system.

In JACS (version 3.0) 1,551 subjects were given a four digit code. These are grouped into 164 two digit Principal subjects. Principal subjects are grouped into 9 Subject areas each with single letter code.

View all four digit JACS 3.0 codes View JACS 3.0 Principal subjects and Subject areas

On this page: History | JACS specification | Course codes | Apportionment | Subject areas | Science marker

History

The JACS system was co-owned and maintained by HESA and UCAS. JACS version 1.7 was introduced in 2002/03 (replacing our former ‘HESACODE’ system of HESA subject codes). It has been revised twice, with JACS 2.0 coming into effect in 2007/08 and JACS 3.0 in 2012/13.

Timeline:

For reference see also: mapping documents and information about the consultation which led to the creation of JACS 3.0.

Specification of JACS

All JACS subject codes consist of a letter followed by three digits, the first of them non-zero (except the generic codes described below). The initial letter identifies the subject group, for example F for physical sciences. The initial letter and immediately following digit identify the principal subject, for example F5 Astronomy. F500 is a valid JACS code used where there is no need for a higher level of precision, but subjects can be identified more precisely using a second non-zero digit, for example F520 Space & planetary sciences, and with even more precision, F521 Space science and F522 Planetary science. It is often necessary to consider together all the codes, or all the student numbers, falling within a principal subject. This is done through reference to the first two characters, so F5 refers to all of astronomy and to total numbers in it, by no means all of which will have code F500. Similarly, F52 refers to the whole of space and planetary sciences.

JACS 3.0 and JACS 2.0

For 2012/13, a review of a selection of the existing subject areas of the JACS coding system resulted in the implementation of a revised 'JACS 3.0' version of the coding frame. The JACS 2.0 version it replaced had been in existence since 2007/08. JACS 3.0 and JACS 2.0 are not directly comparable at any level other than subject area, although many codes were retained in the newer coding frame.

JACS documentation

This page offers an overview of the JACS structure, course coding approach, apportionment rules and the subject codes groupings and SET market that can be used for longitudinal analysis across multiple versions of JACS. A body of additional supporting information is available about the various versions of JACS, at the following links:

Course codes

Student courses often involve combinations of subjects, and so cannot be described by a single JACS code. Within the HESA student data collections, there are two mechanisms for dealing with this. First, JACS has been slightly extended to allow codes to be assigned to highly integrated courses which cut across principal subjects. Where such a broadly-based course falls within a single subject group, it can be coded as the group letter followed by three zeroes, for example F000 would code such a course in physical sciences. This is known as a generic code, and is an extension of JACS for the purpose of coding complete student courses; generic codes may not be used in any other way, for example for coding modules. Courses which cut across subject groups are given the generic code Y000, which is equivalent to continuing to recognise the need for a combined subject group. The second mechanism is designed to describe less integrated courses of the kind often known as Joint honours. The HESA Student record allows the reporting of up to three subject descriptors for each course and a proportion of time allocated for each subject studied on a course.

Apportionment

Under apportionment, each student instance is, where necessary, divided in a way that reflects the pattern of a split course. This is analogous to the use of FTE calculations (with a variation for initial teacher training (ITT) students).

For split courses not involving an ITT component, HE providers assign their own percentages based on a broad assessment of the relative contribution of subjects to a course, rather than detailed analysis of the contributions of subjects to individual students' courses of study. It is therefore expected that most HE providers will apply the same percentages to all courses and only vary this where there is a substantially different subject split. For HE providers in England, Northern Ireland and Wales the listed standard percentages are recommended, and in Scotland obligatory:

  • Balanced 50% for each of the two subjects,
  • Major - Minor 67% and 33%,
  • Triple 34%, 33% and 33%.

The sum of the proportion allocated to each subject studied on a course must equal 100.

ITT students at undergraduate level who also have specialism subjects recorded (typically, secondary ITT students) are apportioned 50% to the 'Education' subject area and the remaining 50% is further assigned according to the percentages recommended above. Where no subject other than education is recorded, or where the student is on a PGCE course, apportionment is 100% to the 'Education' subject area.

Subject areas

HESA has defined nineteen subject areas in terms of JACS codes for reporting information broken down by subject to present a set of distinct categories that can be compared over time. The subject areas do not overlap, and cover the entire range of JACS principal subjects.

Since initial teacher training data is presented on a count of instance basis rather than an apportioned basis, the figures are not directly comparable with the apportioned figures in the 'Education' subject area, and are tabulated separately to reduce the risk of misinterpretation.

Apart from the need to separate the 'Mathematical science' and 'Computer science' elements of principal subjects G0 and G9 in JACS 2.0, these subject areas are expressed entirely in terms of JACS principal subjects, and correspond closely to JACS subject groups.

JACS 3.0

Subject areas

JACS 3.0 code

Medicine & dentistry

A

Subjects allied to medicine

B

Biological sciences

C

Veterinary science

D1, D2

Agriculture & related subjects

D0, D3, D4, D5, D6, D7, D9

Physical sciences

F

Mathematical sciences

G

Computer science

I

Engineering & technology

H, J

Architecture, building & planning

K

Social studies

L

Law

M

Business & administrative studies

N

Mass communications & documentation

P

Languages

Q, R, T

Historical & philosophical studies

V

Creative arts & design

W

Education

X

Combined

Y

Total - Science subject areas has been added to certain analyses. This is the sum of the following subject areas: medicine & dentistry; subjects allied to medicine; biological sciences; veterinary science; agriculture & related subjects; physical sciences; mathematical sciences; computer science; engineering & technology plus architecture, building & planning (i.e. sum of JACS codes A to K inclusive).

JACS 2.0

Apart from the need to separate the 'Mathematical science' and 'Computer science' elements of principal subjects G0 and G9 in JACS2, these subject areas are expressed entirely in terms of JACS principal subjects, and correspond closely to JACS subject groups.

Subject areas

JACS 2.0 code

Medicine & dentistry

A

Subjects allied to medicine

B

Biological sciences

C

Veterinary science

D1, D2

Agriculture & related subjects

D0, D3, D4, D5, D6, D7, D9

Physical sciences

F

Mathematical sciences

G00, G01, G1, G2, G3, G90, G91

Computer science

G02, D4, D5, D6, D7, D92

Engineering & technology

H, J

Architecture, building & planning

K

Social studies

L

Law

M

Business & administrative studies

N

Mass communications & documentation

P

Languages

Q, R, T

Historical & philosophical studies

V

Creative arts & design

W

Education

X

Combined

Y

Apportionment at principal subject level

Although subject areas provide a framework for presenting information, a more detailed breakdown to JACS principal subjects is used in some analyses. Again, a process of apportionment is necessary, and the procedure is consistent with that used for subject areas, as follows:

  • For split courses not involving an initial teacher training (ITT) component, the apportionment algorithm is as reported by the HE provider.
  • ITT students at undergraduate level who also have a specialism subject recorded (typically, secondary ITT students) are apportioned 50% to the 'X1 Training teachers' principal subject and the remaining 50% is further apportioned according to the algorithm for non-ITT students. Where no subject other than education is recorded, or where the student is on a PGCE course, apportionment is 100% to the 'X1 Training teachers' principal subject.

JACS science marker

The JACS science marker classifies the following subject groups as science subjects (sometimes called SET -  Science, Engineering and Technology or STEM – Science, Technology, Engineering and Maths):

  • (1) Medicine and dentistry
  • (2) Subjects allied to medicine 
  • (3) Biological sciences
  • (4) Veterinary science 
  • (5) Agriculture and related subjects
  • (6) Physical sciences
  • (7) Mathematical sciences
  • (8) Computer science
  • (9) Engineering and technology
  • (A) Architecture, building and planning

Please note that there is no consistent definition for SET/STEM/Science subjects, the above grouping is used within the Heidi Plus system however other specified groupings can also be requested.