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Specification and Uses of Information Systems


We are currently in the process of updating this chapter and we appreciate your patience whilst this is being completed.


Some definitions

Data are raw items collected.

Information is the result of applying various transformations to data ('processing') to derive something perceived as meaningful. Note that this depends to an extent on the perceiver.

Knowledge is a structure wherein information is interpreted and used as a step towards a conclusion of action. It may be expressed in a formal way that computers can use; it may be implicit in organisational behaviour; or it may exist only in the minds of users.

Data: 95, 171
Information: process the data into the form 171/95: Systolic pressure 171, Diastolic pressure 95
Knowledge: The figures represent undesirably high blood pressure, which should be  monitored and may be treated. (Normal pressure would on average be near 120/80).

The health sector is a very data-intensive system.

Information systems should be specified in the first instance by their required outputs, i.e. they should be purpose-driven. From these outputs are derived the data input and the various transformations to the data which are needed to arrive at the desired information. All too often, though, health information systems have been technology driven, without sufficient thought being given to the service purpose they are intended to fulfil. In general, information systems model the business processes of their organisations, and when these change, the specification (and therefore the system functions) also change. This is a prime reason why large scale health computer systems have been much criticised: systems specified and implemented for one business model are often shoehorned to work under another incompatible structure, and inevitably fail to some extent. A classic example in the NHS was ‘NPfIT’ - National Programme for IT in the NHS.

“The core aim of NPfIT was to bring the NHS’ use of information technology into the twenty-first century, through the introduction of integrated electronic patient records systems, online ‘choose and book’ services, computerised referral and prescription systems and underpinning network infrastructure. Despite the failure of many of these services to be delivered, the government, and ultimately taxpayers, incurred significant costs for the programme, including contract transition and exit costs which continue to accrue in 2013/2014.”[i] and [accesssed 22/08/2018]

Systems are also specified (in a slightly different sense of the word) in terms of access and confidentiality – e.g. what password restrictions or  physical separation the system should have.

The process of specifying information systems is multi-layered, involving a range of formalisms and methods that are the province of computer scientists rather than public health people. Users such as public health staff need understand the outputs they are provided with, and that the systems meet security and confidentiality requirements, but need not concern themselves directly with the more technical aspects of the process.

Many information systems in the health service derive directly from the administrative processes within the health service such as admitting and treating a patient in hospital or running a diagnostic department. Such administrative systems are often available at reduced cost as they are a ‘spin off’ from information already collected, but reporting can vary depending on the importance of the information for the original purpose(s).

For most Public Health work, the information available is collected for other purposes (e.g. recording acute care) and the data item specifications, together with professional knowledge of how and why the data are collected, are what we mostly have to work from. For the main NHS systems the NHS data model and dictionary sets these out in detail: [accessed 22/08/2018]

The drawing together of different data sources to produce comparative information and knowledge is a key requirement of public health work. Public Health England has been developing useful tools for this purpose. In particular, the Public Health Outcomes Framework allows comparison of key health indicators across different areas:

A wide range of Public Health data and analysis tools is also available at:

An important data dictionary for public health people is the Hospital Episode Statistics data dictionary:  [accessed 22/08/2018]

It should be borne in mind that though Information Technology (IT) generally refers to the use of computers and telecommunications technology in information systems, manually maintained pencil-and-paper records still constitute information systems.



                                                            © M Goodyear 2008, D Lawrence 2018