Post-occupancy evaluation (POE) is intended to determine how well an operational facility matches end-user requirements. Put simply, is the design and construction fit-for-purpose from an end-user perspective? Whilst a POE has long been required by facility owners, operators and tenants, its importance in the public sector has been substantially raised under the UK's Government Soft Landings (GSL) framework.
GSL is, essentially, a set of detailed policy documents that spells out requirements for a facility from cradle-to-cradle. The term "soft landing" reflects the need for a smooth transition from the design and construction phase to the operational phase of the facility. When combined with POE, it supports comparison between the required performance outcomes and actual performance outcomes. This is achieved by measuring the following.
Functionality & Effectiveness – buildings to be designed to meet the business and social performance requirements and needs of the occupiers as well as providing healthy, safe, effective, productive and appropriately attractive working environments.
Environmental Performance – designed to meet UK Government performance targets in energy use, carbon dioxide emissions, water usage and waste production.
Cost performance – meeting government capital and operational cost targets.
In general, a POE would be expected to assist in a number of ways that include the following key aspects of design and construction in regard to the facility's fitness-for-purpose:
- obtaining structured feedback to help in fine-tuning the facility in general and optimising the performance of building services engineering installations in particular;
- resolving persistent or recurrent problems in a facility that might otherwise go unchallenged; and
- providing information and data for facility planners and designers to support them in the planning and/or design of future facilities.
Garnering the opinions of end-users can be expected to provide an objective basis for evaluating the extent to which the facility is providing what was intended, so long as the method is rigorous. The normal method of undertaking such an evaluation is to conduct a survey of end-users using a questionnaire and might also involve interviews as a follow-up activity.
Questionnaires are the most common tool for eliciting opinions and care needs to be exercised when drafting one. To do the job properly requires more than a few hours of work. There are two golden rules: first, the more time spent on designing the questionnaire the greater will be its usefulness; and, second, no questionnaire should ever be distributed unless it has been piloted and found to be fit for purpose.
A post-occupancy evaluation differs from many conventional surveys because it seeks the opinions of those directly affected. The worth of any evaluation will depend on how well it has been designed and conducted, not least the extent to which it aligns with the facility management strategy, the design brief and functional requirements, since each of these help to establish a baseline against which actual performance of the facility can be measured. Interviewing end-users is one way of eliciting those opinions and any questionnaire used for this purpose will have to be properly structured if the data collected by them are to be analysed in a meaningful way. In the course of a survey or interviews, it is possible that some end-users will be reluctant to discuss issues.
The entire process could take a long time if any sample has to be representative. In most cases, claims to representativeness should be verified statistically to avoid misunderstanding over any inferences that might be drawn on behalf of all would-be respondents; in this case, all end-users. In many cases, the population of end-users from which a sample is drawn will be known, perhaps exactly. However, different groups of end-users might have to be considered, where each can be considered as a population in its own right. The point is that over or under-representation in any sample and in subsequent responses has to be avoided.
When preparing questions it is better to adopt an approach where respondents (i.e. end-users) can indicate the extent to which they agree or disagree with a statement about their situation or the extent to which they are satisfied or dissatisfied with aspects of the facility. Questions that require a simple yes or no are unlikely to provide anything meaningful and can also leave respondents feeling frustrated that their opinions have not been properly considered. The best tactic is to allow respondents to express their feelings about those matters they believe are important and about which there is concern. It is not wrong to ask standard questions through which to establish some basic facts; however, other questions should be asked to help understand what end-users truly experience.
The use of a five or six-point Likert scale can be useful in eliciting opinions and measuring experiences, with additional open questions used to capture free-form responses. There is, however, some criticism over the use of self-evaluations based on Likert scales, which is concerned with error. Care needs to be exercised when analysing responses and, wherever possible, measures of association involving correlation should be considered for the purpose of statistical analysis in preference to simpler, numerical scoring. In most cases, it is as important to understand the extent to which respondents in a sample are in agreement on the various issues before them as it is to know which are rated highly and which are not.
Evaluations can also help to draw-out suggestions from personnel about how to improve their well-being and that of the organization. Means for reducing waste, pollution and energy can be found when personnel are motivated to make suggestions in the belief that they and their feedback will be taken seriously. Finally, it is important to stress that a post-occupancy evaluation should not be seen as a one-off exercise. For it to be of benefit, it has to be repeated. In between times, personnel must be provided with the results and details of how the organization intends to deal with any issues that have arisen.
Further information on Government Soft Landings, including downloadable documentation, can be found under the work of the Building Information Modelling (BIM) Task Group.