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SSA Toolkit

Describe system

 

Describe system

Describe system

Producing a more detailed, graphical description of the system

This section looks at how to construct a more detailed, graphical description of the system being examined. This is important because it helps to identify all the main areas where things could go wrong, making sure that everything is covered and providing a robust basis for the SSA. Most importantly it helps to provide a shared understanding of the system being assessed.

On this page:

Describe the system is the final activity in the Examine phase

Describe system is an activity in the Examine phase of SSA


Mapping the system

It is important to construct a map of the system being examined, where a system is defined in this context as an integrated set of elements (with a purpose). It may include people, activities, consumable products, equipment, care practice, paper records, management structures, training regimes, environmental conditions, and so on.

A map of the system is a detailed description of the system, usually focusing on just a few of these elements, for example the activities and processes being examined in the SSA. It identifies the elements, and shows how they are linked together and linked to other systems. The map is normally produced in graphical form, but in some cases may take the form of a bulleted list of activities, for example.

A system map helps to clarify what is going on and to make sure no important elements are forgotten. The map can be used to systematically identify risks, by considering the possible problems in each part of the system. It can also help to identify additional stakeholders, by questioning who is associated with each part.

There are many different methods for mapping systems, of which some are better at capturing certain aspects of a system, and some are easier to use. For an SSA, it is recommended to start by creating a process map. This has several advantages: it describes processes (which are usually central to a system), is often used to describe systems in healthcare, is fairly straight-forward to construct, and in most cases is sufficient.

People who are familiar with system mapping and have an unusual type of system may decide to start with another method. For example, they may find it useful to create a communication diagram, particularly if the system or the SSA focuses on the movement of information, documents or other artefacts. An introduction to describing systems, which covers a variety of description methods, is available for download from the Resources page.

Putting ‘Mapping the system’ into practice

Space to record this information is provided in the SSA Assessment Form. To do this:

  1. Select the ‘Describe system’ page in the Assessment Form.
  2. Enter the map(s) of the system in the box labelled Description of the system (using diagrams).
  3. Copy the page if more space is required.
Screenshot of Describe system page of the assessment form

 


Case Study

The completed ‘Describe system’ page from the Section 136 case study is shown opposite. Further explanation of this stage in the case study can be found on the Section 136 page about Mapping the system.


Further information

An Introduction to describing systems is available for download from the Resources page.


General principles for mapping systems

When mapping the system, it is helpful to keep in mind various principles or guidelines.

First of all, choose a mapping method that is suitable for the team conducting the SSA. There are many different methods available, including process mapping and communication diagrams described below. We recommend starting by drawing a process map, unless the team is very familiar with system mapping. It can be helpful to have more than one diagram, and to use one or possibly more mapping methods, in order to represent a system comprehensively. It may be necessary to trade comprehensiveness with time available.

Once the mapping method(s) have been chosen, there are some further principles to keep in mind:

a) To begin with, draw a high-level description which shows the main elements of the system that are of interest. More details can be added later.

b) If an existing system is to be mapped, then represent the system as it is, not as it should be. This will be much more useful in determining where risk is actually occurring.

c) Use symbols and labels consistently, and do not miss labels off because they might appear to be obvious. Remember the diagram may be read by someone who is not as familiar with the system as the person producing the map, and this may be some time in the future.

An example of a system map, with boxes representing the steps in the process, and arrows indicating the order in which these steps occur.

Example of a system map

d) Discuss things as a group. If the diagram is drawn on a white board or large sheet of paper, it can make it easier for people to contribute than if it is drawn electronically. The diagram can easily be photographed to transfer it to electronic form.

e) Consider writing the parts of the system on sticky notes. This allows things to be easily moved around and to be added in. Use different coloured notes to represent different things (e.g. activities, decisions or documents), or draw shapes around each element that will be used in the final diagram.

f) Record other comments and suggestions, but try to keep these separate from the main system map to avoid it getting confused. For example, write them on a distinct coloured note.


Setting boundaries

After drawing the system map, it is useful to define explicitly the boundaries of those parts of the system that will be studied during the SSA. This assists focus, and avoids wasting time and effort. To achieve this, it can be helpful to describe a system that is more extensive than the one which is to be studied and then define the boundary of interest within that description. This has the advantage of highlighting those parts of the larger system that interface with the system under study. This can also show further SSAs that might need to take place in the future, and can help to identify issues that can occur at these boundaries.

For example, the wider system might include the whole process of admitting a young person to a mental health facility, starting from that person being arrested by the police, whereas the area of particular interest might focus only on the activities that take place at the unit itself. Further SSAs might be held with the police, at a later date.

Setting these boundaries refines the required scope of the assessment, which should then be updated by visiting the Outline goals activity.

A red border has been drawn round some of the steps in a process map

Example of boundaries drawn on a system map

Putting ‘Setting boundaries’ into practice

Space to record this information is provided in the SSA Assessment Form. To do this:

  1. Select the ‘Describe system’ page in the Assessment Form.
  2. Highlight the parts of the system map(s) that will be focused on in the SSA.
  3. Revise the Scope of the assessment on the ‘Outline goals’ page, if appropriate.
Screenshot of Describe system page of the assessment form

 


Case Study

The completed ‘Describe system’ page from the Section 136 case study is shown opposite, with the boundaries marked on the system map in red. Further explanation of this stage in the case study can be found on the Section 136 page about Setting boundaries.


Method 1: Process maps

Process maps are one method of mapping a system. They describe processes, where a process is defined as ‘a series of connected steps or actions [required] to achieve an outcome’ (NHS Institute for Innovation and Improvement, 2005). One such map is the flow diagram. These may already be familiar to members of the team, and it may therefore be helpful to use their standard notation.

In general, a process map may include the following elements:

  • Boxes, which describe tasks or activities;
  • Arrows, which connect the boxes and show the order in which things occur;
  • Diamonds, which represent decisions or conditions, determining which activity happens next in response to a named outcome.

In the example opposite a sequence of activities culminates in a decision: the question ‘Is the toast brown enough?’, with two possible named outcomes.

 

 

 

 

 

In process mapping, it is often helpful to start by focusing on what happens to the patient, although other points of focus may occasionally be useful. For example, in studying the use of medical records, it might be helpful to think about what happens to the records rather than the patient directly.

A patient-centric view also provides a good starting point when mapping a complex process which also involves a mix of other types of elements, e.g. diagnostic tests, report writing or the transfer of records. These additional elements can be added to the process map later. For example, the diagram on the right shows a simple process map for describing a patient-focused view of a visit to a clinic.

 

 

 

 

 

 

 

 

 

Once the core patient journey has been described, other things that take place can be added. This may involve adding elements between the existing boxes as well as new parallel pathways.

For example, between a blood test being carried out on a patient and the patient receiving the results, the blood sample must be sent to the laboratory, processed, and the results sent back. These steps could be added between the steps ‘Patient waits’ and ‘Patient receives results’, i.e. in parallel with the patient seeing the nurse and waiting for the results.

A process map, with the following steps in boxes with arrows between them: Put bread in toaster, Push bread down and press button, Bread pops up. There is then a decision in a diamond shape: Is the toast brown enough? One arrow from this is labelled yes, and goes to a box lablled Eat toast. Another arrow is labelled no and goes back to the box with Push bread down and press button.
Simple example of a process map for making toast

A process map, with the following steps in boxes with arrows between them: Put bread in toaster, Push bread down and press button, Bread pops up. There is then a decision in a diamond shape: Is the toast brown enough? One arrow from this is labelled yes, and goes to a box lablled Eat toast. Another arrow is labelled no and goes back to the box with Push bread down and press button.

Example of a simple patient journey

 

The previous process map has been expanded with extra steps between Blood sample taken and Patient receives results. The extra steps are: Blood sample sent to lab and Blood sample processed. These occur in parallel with the patient journey.

Expansion of the patient journey

Putting ‘Method 1: Process maps’ into practice

Space to record a process map is provided in the SSA Assessment Form. To do this:

  1. Select the ‘Describe system’ page in the Assessment Form.
  2. Enter the process map in the box labelled Description of the system (using diagrams).
  3. Copy the page if more space is required.
Screenshot of Describe system page of the assessment form

Case Study

The completed ‘Describe system’ page from the Section 136 case study is shown opposite. Further explanation of this stage in the case study can be found on the Section 136 page about Method 1: Process maps.

 

 

 

 

 


Further information


Method 2: Communication diagrams

Another method of mapping a system is to construct a communication diagram. Communication diagrams describe the information flows within a system. This can be particularly helpful in highlighting interactions between Trusts, departments and individuals, complementing the description of activities present in a process map. It shows how information and materials move between people or groups of people (stakeholders) linked by some common process.

The communication diagram uses rectangles to represent people and arrows to describe the information and material flows. Adding a number to each arrow can also show the order in which things happen.

Communication diagrams can also be used as a basis for risk assessment by considering the possible deviation or failure of the flows and/or absence of the stakeholders.

 

Example of a communication diagram showing the flow of information and medicine between five entities in the system: The ward, transitional care team, hospital pharmacy, home/care/interim beds, and general practitioners. Information and medicine flows are marked with arrows between the entities, and numbered in the order in which they occur. For exmaple, there is an arrow between the ward and the transitional care team labelled 1 assessment notification.

Example of a communication diagram

 

Putting ‘Method 2: Communication diagrams’ into practice

Space to record a communication diagram is provided in the SSA Assessment Form. To do this:

  1. Select the ‘Describe system’ page in the Assessment Form.
  2. Enter the communication diagram in the box labelled Description of the system (using diagrams).
  3. Copy the page if more space is required.
Screenshot of Describe system page of the assessment form

Case Study

A communication diagram was not produced for the Section 136 case study, as explained in more detail on the Section 136 page about Method 2: Communication diagrams. Communication diagrams were produced in other case studies (e.g. Trauma network and Medical records) and may be added to this website later.


Further information

  • Holt (2007)'s book ‘UML for Systems Engineering: Watching the Wheels’ gives more information about systems modelling, including communication diagrams. (Published by Institution of Engineering and Technology)