The study of healthcare is founded upon a few basic ideas like the cell or the concept of disease. Informatics is similarly built upon the concepts of data, models, systems and information. Unlike health, where the core ideas are usually grounded in observations of the physical world, these informatics concepts are abstract ideas. As a consequence, they can be difficult to grasp, and for those used to the study of healthcare, often seem detached from the physical realities of the clinical workplace .
Models are abstractions of the real world .
What is a model and what does it do? Models are commonplace in our everyday lives. People are familiar with the idea of building model aeroplanes , or looking at a small-scale model of a building to imagine what it will look like when built. In health, models underlie all our clinical activities .
Models actually serve two quite distinct purposes, and both of these are of interest . artificial heart is based upon two kinds of model. Firstly, the cardiovascular system has to be modelled, and secondly, a mechanical blueprint is used to model the way the heart will be constructed.
When artefacts are created, it is assumed that they too will be used for a particular purpose. If the purpose changes, then a design becomes less effective. Thus, the physical design of the waiting room and treatment areas for a general practice clinic will assume a certain number of patients need to be seen during a day, and that certain kinds of therapy will be given. If the clinic was bought by radiologists, they would have to remodel the clinicâs design to incorporate imaging equipment, and to reflect a different throughput of patients . we can consider a particular treatment of a disease written in a textbook to be a template for what should be done to any given patient. If that treatment was based upon assumptions about the incidence of diseases in a given population, then it may not work well if attempted in a different one. Treating infant diarrhoea in a developed nation is not the same task in underdeveloped nations where poorer resources, malnutrition, and different infecting organisms change the context of treatment. Before a model is used, one therefore has to be clear about what has actually been modelled. This is because, when models are created, the circumstances at the time have a strong influence on the final value of the model. Similarly, a set of rules and procedures might be developed in one hospital, and be spectacularly successful at improving the way it handles its cases. One would have to be very cautious, given that these procedures implicitly model many aspects of that particular institution, before one imposed those procedures on other hospitals. Very small differences, for example in the level of resources, type of patients seen, or experience of the staff, may make what was successful in one context, unhelpful in another.
More generally, any designed artefact, whether it is a car, a drug or a computer system, has to be designed with the world within which it will operate in mind. In other words, it has to contain in its design a model of the environment within which it will be used. These specifications constitute its design assumptions. Thus there is a connection between the process of model creation, the construction of artefacts based upon such models, and their eventual effectiveness in satisfying some purpose .
Models are the basis of the way we learn about, and interact with, the physical world.
Models can act either as copies of the world like maps, or as templates that serve as the blueprints for constructing physical objects, or processes.
Models that copy the world are abstractions of the real world:
Models are always less detailed than the real world they are drawn from.
Models ignore aspects of the world that are not considered essential. Thus abstraction imposes a point of view upon the observed world
Many models can be created of any given physical object, depending upon the level of detail and point of view selected.
The similarity between models and the physical objects they represent degrades over time.
There is no such thing as a truly general-purpose model. There is no such thing as the most âcorrectâ model. Models are simply better or worse suited to accomplishing a particular task.
4. Models can be used as templates and be instantiated to create objects or processes that are used in the world.
Templates are less detailed than the artefacts that are created from them.
An artefact is a distortion of the original template.
No two physical artefacts are similar even if they are instances of the same template.
The effect of an artefact may change while the original template stays the same.
The process of creating an instance has a variable outcome, and the impact of the instance of an artefact in the real world also varies. As a consequence, there is no such thing as a general purpose template. All we can have are templates or designs that are better or worse suited to our particular circumstances and task.
5. The assumptions used in a modelâs creation, whether implicit or explicit, define the limits of a modelâs usefulness.
When models are created, they assume that they are to accomplish a particular purpose.
When models are created they assume a context of use. When objects or processes are built from a model, this context forms a set of design assumptions.
6. We should never forget that the map is not the territory and the blueprint is not the building
A 50-year-old woman with a past history diabetes and alcohol and IV drug abuse, presents with symptoms of abdominal pain and vomiting and is diagnosed as having âacute chronic pancreatitis.â Her amylase and lipase levels are normal. She is admitted and treated with IV fluids and analgesics. On hospital day 2 she begins having spiking fevers and antibiotics are administered. The next day, blood cultures are growing gram negative organisms.
At this point, the service is clueless about the patient’s correct diagnosis. It only becomes evident the following day when (a) review of laboratory data over the past year shows that patient had four prior blood cultures, each positive with different gram negative organisms; (b) a nurse reports patient was âbehaving suspiciously,â rummaging through the supply room where syringes were kept; and (c) a medical student looks up posthospital outpatient records from 4 months earlier and finds several notes stating that âthe patient has probable Munchausen syndrome rather than pancreatitis.â Upon discovering these findings, the patient’s IVs are discontinued and sensitive, appropriate followup primary and psychiatric care are arranged.
A postscript to this admission: 3 months later, the patient was again readmitted to the same hospital for âpancreatitisâ and an unusual âmassive leg abscess.â The physicians caring for her were unaware of her past diagnoses and never suspected or discovered the likely etiology of her abscess (self-induced from unsterile injection
Coiera, E., & Coiera, E. (2003). Guide to health informatics (2nd ed., pp. 31-37). London: Arnold ;.