Human factors integration
2.5 Starting an HFI programme
2.5.3.2 Early human factors analysis
The need to address a wide range of HFI issues early in the life of a project has led to the development and use of Early Human Factors Analysis to ensure the fullest consideration of all relevant TAs and TIs. This technique is so important that it is described more fully below. It will lead to the identification and prioritisation of TAs along with their associated risks, strategies to mitigate them and resources required (including personnel, equipment, schedule and costs). In turn this may provide valu- able source material for the specification of an HFI programme and its contribution to the TLMP.
2.5.4 Development
While requirements definition and analysis is associated with concept, development is associated with the architectural design process: the synthesising of solutions.
The TAs and associated risks will have been identified in concept at a high level.
The list identified in the case of Table 2.2 is expanded and developed in Table 2.3.
This is the most critical stage for HFI – if risks are not addressed here they will become increasingly expensive to mitigate and if not handled effectively the risk will be transferred to the utilisation and support stages – the operators, maintainers and support staff will shoulder the consequences.
Each of the TIs and risks will need to be addressed or given a reason for no action. This will form the basis of the updated TLMP which will be carried through the project for the remainder of its life cycle.
Exemplar strategies to be considered for the clarification of the issues (in the case of the system described in Table 2.2) and implemented in the development stage include:
• Operational analysis is required to provide the context against which all HFI work will be judged. Clearly the HFI element will not be the lead here (this will probably be led by experts in the likely use of the equipment) but the work will form part of the HFI programme, and may influence important aspects of equipment design, manpower and safety.
• Watchkeeping schedules and team organisation. The allocation of tasks between individuals within a team and the allocation of individuals to schedules may be entirely known for an established system but equally may by itself be subject to investigating as new demands are encountered. The selection of watchkeeping schedules may have important implications for manpower levels and safety, and hence require investigation.
Table 2.3 A brief description of possible TAs and TIs. (Such a list of TAs and TIs could easily be used on the customer side to develop a list of requirements, and hence acceptance tests [12])
Technical areas Brief description of the technical issues
Operational scenario The complete set of tasks and goals to be achieved in all scenarios, by the whole system needs to be described.
The set of tasks and goals to be achieved needs to be analysed into their components so that the contribution of the equipment and the contribution of the users can be fully described.
The operational rules to be followed in all scenarios shall be fully described so as to ensure a good match with job and task design.
Team organisation and integration
The organisation of the various teams, and their integration within the total system in which the users operate, maintain or support the system shall be considered.
Manpower The total number of users, maintainers and support personnel shall be specified along with a statement of their roles and responsibilities.
The manpower requirements shall be considered to take account of through-life issues.
User characteristics The equipment design needs to match the likely quality of the personnel available at the time of operation. This shall take account of:
• employment legislation
• anthropometric characteristics
• educational and training background
• operational experience
• mental capabilities.
Mission critical tasks, human–computer interaction and operability
A set of mission critical tasks should be identified for assessment and acceptance purposes. These should be agreed with the appropriate authorities.
Performance requirements shall be met for mission critical tasks. These may refer to both individual and team achievement levels.
High levels of operability and interoperability should be achieved through the use of standardised design features.
The design of human–computer interaction should aim for ease of operation and training.
The layout of the displays and controls should take full account of the characteristics of the potential users.
Equipment layout The layout of the workstation shall take account of the need for users to work in a seated position while others may be positioned around it.
Full account shall be taken of reach and visibility requirements.
Table 2.3 Continued
Technical areas Brief description of the technical issues
Equipment layout The design of the room accommodating the workstation shall make full allowance for ingress and egress, especially in emergency conditions.
A chair shall be provided that shall accommodate a specified set of the likely user population and adequately protect the seated person from hazards as defined by the operational scenario.
Maintenance The need for maintenance needs to be fully considered so that access can be provided.
The need for full time maintainers should be identified.
Equipment should be designed for ease of maintenance to avoid the need for highly skilled manpower.
Training The training needs arising from the design of the equipment and likely TAD shall be fully identified.
The possibilities for training aids to be built into the equipment should be considered.
The training facilities should take account of the needs for individual and team performance assessment and debriefing.
Environmental conditions
The habitability standards shall be met to ensure the comfort of the users.
Full account shall be taken of the noise, heating, ventilation and lighting levels when assessing the users’ performance on mission critical tasks.
The design of the displays shall take account of the requirements for any special lighting conditions, e.g. high levels of ambient lighting or the use of red lighting.
System safety System safety will be investigated and the equipment designed to ensure that there is as low as possible a risk from accidental damage to the user or the equipment.
Health hazard assessment
Health hazards will be investigated and a hazard analysis performed to ensure that there is as low as possible a risk of injury to the user.
• User characteristics. The techniques for estimating the manpower requirements will have to take into account at least two classes of tasks: those specifically related to the equipment and events under the users’ responsibility and those that belong to the responsibility of the wider community within which the equipment is located.
The manpower requirement will, in the first instance, be determined by functional analysis but will then take into account such issues as health and safety levels and employment policy. The risks here include the system’s effectiveness and WLCs. They may also include availability for utilisation due to poor availability of trained personnel.
• The size, shape, strength and stamina of the personnel will require definition, along with their training background, educational attainment and background experience shall be specified. The derived document is conveniently known as a Target Audience Description (TAD). Increasingly the use of highly detailed TADs is becoming the norm in many spheres of equipment acquisition and engineering.
Failure to comply with appropriate norms may result in very costly re-engineering in later stages to overcome problems that can be handled routinely during earlier development.
• Manpower/personnel analysis will be required to ensure that requirements of design drivers are met.
• Human–Computer Interaction (HCI) – mission critical tasks and operability. For many computer-based systems associated with control, this may be seen as a critical area. Its importance is entirely dependent upon the operational require- ments, Safety Integrity Levels (SILs) and automation. Derisking strategies may involve the use of simulations, technical demonstrators and mock-ups of many varieties. For systems such as those found in avionics it may involve expensive work with high fidelity equipment, but equally a cardboard model may suffice for others. The consequences of failure here may include system effectiveness, low levels of operability (including high levels of errors) and reworking at a later stage at substantial expense. Further information on HCI and usability is provided in Chapter 11 of this book.
• Equipment layout. Stories of failures to understand layouts effectively are legion and failure may be expensive depending on the situation. Poor layout may not only mean inconvenience but can also mean increased manpower levels or safety risks. A thorough knowledge of the TAD and users’ tasks, is essential in this stage to ensure that characteristics such as reach, visibility and communication are correctly estimated. This information is likely to be important not only to HFI specialists but others associated with the broader aspects of system engineering.
The strategy here will be to seek to optimise the use of space.
• Maintenance. Increasingly with the concept of WLC, the major personnel costs associated with a system lie with the manpower levels and as a consequence maintenance staff may make up a major proportion of the personnel assigned to a system. This aspect carries with it elements of human engineering to ensure maintainability, and manpower to carry out the work and safety levels. This work will feed into the manpower specifications, training and human engineering.
Allied to maintenance is support, and together these may be major manpower drivers. Maintenance and support strategy may well need to take full account of any Integrated Logistic Support (ILS) concepts.
• Training. Costs associated with training and the means of training delivery have changed substantially over the last decade. Training Needs Analysis and Training Media Analysis are required early to ensure that training targets can be met to budget and schedule. Given that it frequently takes two years for a system to reach peak effectiveness with effective training, a failure in this area may have substantial effects of performance. Of course, the training and career paths of the system personnel may well take place over a number of years. The training
strategy needs to take full account of the equipment development strategy, or there may be penalties of costs and schedules.
• Environmental conditions. Failure to meet standards in this case may vary greatly dependent on whether these are part of a life support system or merely supporting the comfort of the users. The risks here may vary substantially depending on the location of the system and hazards that might be expected. A full specification will be required early to ensure that any consequences for the broader aspects of system engineering may be taken into account.
• System safety. It is now standard practice to develop a safety case associated with any new procurement/design work. The risks of failure here are multitudinous depending on the application. Within the MoD the ALARP principle has been adopted to provide guidance on how to proceed. The safety case will involve a multidisciplinary approach but the role of the human is likely to be central.
Strategy here may need to be highly integrated with any overall system safety work (see also Chapter 14).
• Health hazard assessment. Work here is required to meet standards such as the Montreal Protocols. The risk here may include the possibility of standards chang- ing throughout the life of the system as a result of legislation. It is most likely that this line of work will feed through directly into the safety case.
2.5.5 Production 2.5.5.1 General
This stage will involve final definition and agreement of HFI issues prior to the start of the production process and progressive acceptance, once the production process has started to yield deliverables.
The production process itself may involve little HFI activity – although there may be human factors aspects of production itself (for reasons of space these aspects are not considered within this coverage). The area of greatest HFI activity will be associated with verification and validation: the definitions used here are in line with those proposed in ISO 15288. (See also Chapter 12 which covers verification and validation in detail.)