Post-occupancy evaluation (POE)

Revision as of 14:10, 9 May 2023

Abstract

In the 1960s, problems in building efficiency, especially from the building user perspective were observed. That led to the emergence of post-occupancy evaluation (POE) as a tool and system that supports the identification and evaluation of critical aspects of building performance ^[1]. Zimring and Reizenstein described POE as the “examination of the effectiveness for human users of occupied designed environments” ^[2].

Nowadays, POE is applied in the building industry, primarily in the early or late stages of project management, with a focus on energy performance, indoor environment quality, occupants’ satisfaction, and productivity ^[3]. Applying POE in the early stages of a construction project helps to reflect on mistakes identified in similar previous projects, optimize the new building according to the most recent standards, and to extend its life cycle. Using POE in the late stages of project management mainly serves as a feedback provider on the performance of a building after construction and occupation.

Depending on the level of detail for each evaluation, three analysis options can be used: indicative, investigative, and diagnostic. Thus, the POE can be a simple walk-through evaluation (indicative), a more detailed and formal data collection (investigative), or a large-scale project review (diagnostic) ^[4].

Introduction

Per definition, a project is “a temporary organization that is created for the purpose of delivering one or more business products according to an agreed business case” ^[5]. Adapting it to the construction industry, a project will be the creation of one or more buildings within an agreed project and design brief. Due to it being temporary, project managers are needed to ensure the targeting of project objectives and performance targets such as for time, cost, quality, scope, benefits, and risks ^[5].

Because projects are mainly case-dependent, gained knowledge is often not shared with a broader group outside the project team and consequently lost in the long term. As a result, similar mistakes are repeated, and slow improvements across projects are observed.

However, projects are how change is introduced, and not using the experiences of former projects will stop this ^[5]. Among others, project management principles are to recognize, evaluate, and respond to system interaction and to enable change to achieve the envisioned future state. ^[6].

To implement change and ensure compliance with project objectives and performance targets in the construction environment, the analysis tool “post-occupancy evaluation” (POE) can be used. The tool helps to highlight problems that can be addressed and solved as well as provide lessons to improve the design and procurement and optimize services ^[7]. Regarding future buildings, it enables the collection of relevant information to impact the design and functionality.

The data can help the industry to avoid the same mistakes and especially save time and money.

History

An evaluation assessing the building performance was introduced in 1960 for the first time. The reason for this was significant problems experienced in the building performance from the occupant’s perspective, first noted in institutional care facilities (hospitals, nursing homes) and correctional facilities ^[1]. Sim van der Ryn & Victor Hsia called it a “Systematic assessment from the occupants’ point of view” and Georg Baird a “Study of the physical environment and emotional sensations experienced by people with office buildings” ^[3]. In 1975, the term “post-occupancy evaluation” (POE) was introduced as the generic term for such assessments which were seen as a logical final step of the cyclical design process in 1981 ^[8].

Among other publications, in 1995 a book on Building Evaluation Techniques was developed with 120 evaluation concepts, techniques, and tools ^[9]. In 2002, the building industry accepted the following definition: “Any activity that originates out of an interest in learning how a building performs once it is built (if and how it has met expectations) and how satisfied building users are with the environment that has been created” ^[3].

POE today

Even though POE already exists for a while and has developed rapidly over the last decade, it is not standard practice yet. However, the importance of evaluating real-time performance is raising and many people are conscious of it. The role of the occupant of the building and its feedback will be an inevitable part of the project development. Currently, many decisions are still based on assumptions. In contrast, POE is used to collect real information and implement them in the evaluation of the building.

However, POEs are still far from being an ingrained part of the building delivery process.

The idea behind the tool

Figure 1: POE

Post-occupancy evaluation (POE) is an analysis tool for the construction environment and a process of obtaining information on the building’s performance. It is common that clients and occupants experience and evaluate a building from different perspectives. Clients have a vision of implementing a smart infrastructure within the building and offering new technologies and solutions, but it is still not ensured that the occupants will be able to handle it. By conducting a post-occupancy evaluation, issues regarding the use of (smart) tools can be identified and solved. Additionally, it will help to learn and avoid problems in future projects.

The evaluation generates a feedback loop and enhances continuous improvement ^[8]. It will usually be undertaken after the building is occupied for a specific time and collects information on energy use and user satisfaction. The feedback will be used to improve the fit between occupants and their building. The main areas that are analyzed are energy performance, indoor environment quality, as well as occupant satisfaction and productivity ^[3].

Next to identifying problems in existing buildings, POE can also be used to test new building prototypes and develop design guidelines and criteria for future projects ^[10].

The tool can be applied in different stages of the project – in its early and late stages (see Application). In early stages, the tool will give feedback from former projects and show lessons learned. Within later stages, it is used to control the actual performance of the implemented (smart) infrastructure and if the occupants are satisfied with the project. Both applications help to evaluate critical aspects and to develop new requirements and functions to implement necessary change ^[8]. Additionally, the information gained in the late stages of a project can again be implemented as lessons learned in new projects and improve the design and operational projects. As shown in Figure 1 the adaption of POE can be a part within the project's life cycle.

Furthermore, the tool can have a positive impact on reaching the net-zero goal. POE ensures the measurement of actual operational energy use by a building which will generate an actual carbon footprint of the building, and none calculated based on assumptions.

Benefits

POE offers various benefits which can help improve existing buildings but serve as learnings for future projects. On the one hand, it will continuously improve the construction environment. Especially the space utilization and reduction of waste but also the reduction of energy use. Within this, costs and time can be saved, and operational expenses reduced. On the other hand, it will validate the real needs of the occupants which will increase the knowledge of architects. Due to the decision making based on real information instead of assumptions, it will enhance the efficiency of space, systems, and equipment. This will lead to an improved competitive advantage for the architect in the marketplace ^[8].

Levels of POE

The evaluation can be subclassified into three levels – indicative, investigative, and diagnostic. The level of detail is increasing with each subclassification.

1. The indicative evaluation is a rapid assessment of the building conditions before the building contract is concluded. It can be conducted as a walk-through evaluation with selected interviews and simple occupant surveys. No reflection on the final performance of the building will be made, but the gained insights will be used to impact future projects ^{[4] [11]}.
2. A more detailed assessment will be made by using the investigative level. The evaluation is conducted by independent evaluators mostly during the second year of occupation ^[11]. To do so, it requires formal data collection techniques, interviews, and questionnaires ^[4]. The results will be used to gain an overview of the physical project outcome and success.
3. The diagnostic POE is the most detailed assessment. It will as well be conducted by an independent evaluator but can start at any time. The evaluation should resolve significant persistent performance issues ^[11]. The diagnostic POE is mostly used for large-scale project reviews, in case of serious problems, or as part of a research project. ^[4]

Application

Post-occupancy evaluation will be applied to obtain feedback on a building’s performance after it has been built and occupied. It is used to gain information on the building itself, its energy use, and on its user satisfaction ^[10].

If it is applied correctly, it can be an important part of the life cycle of the building and especially increase the knowledge gained for future projects.

POE offers a wide range of activities and benefits, including the assessment of building performance, the exploration of relationships between inhabitants’ behavior and building resource use, the optimization of the indoor environment for inhabitants, the development of more thought-through decisions about the future building design and opportunities to enhance the dialogue between the design teams and their partners ^[3].

Briefly, there are three POE methods which can be used in general ^[7]:

• Energy review
• Observe the building in use
• Talk to people: either informally or through surveys/ interviews

Furthermore, POE can be implemented in the early stages but also in the late stages of the product.

Within the early stages, it can be used as feedback from older projects, reflecting on issues that can be avoided, things that can be done differently, or processes that can be improved. Due to an early survey, the wishes of future occupants can be implemented. In the case of the building's energy performance, it can share the knowledge about (smart) tools and the user’s ability to correctly apply them, and if a further implementation is reasonable. In summary, applying it in the early stages can improve the new building by learning from previous mistakes.

By implementing POE within later stages of a project it can be used as a feedback tool to review if the building performance is as intended and if the building meets the outcomes formulated in the project outline. It will show the satisfaction of current occupants and if they are able to work with the provided (smart) tools. In general, it is used as a controlling instrument in a late stage of a construction project.

For proper application of POE, Tom McNeil generated a POE guideline that follows subsequent questions ^[7]:

• What do people think about the building?
• Are people comfortable?
• Do they understand to use of the building?
• How does the building perform in terms of energy and carbon emissions?
• Are the internal environmental conditions healthy and promote wellbeing and productivity?

Above mentioned applications focus on cases within project management. However, an application within portfolio management could be useful as well. Especially companies owning a specific number of buildings and facilitating their portfolio can benefit from POE. The information and knowledge gained from each project can be implemented and shared throughout the organization. This can lead to improvements across all buildings within the portfolio and future projects. Additionally, the organization could establish a standardized practice for its portfolio and furthermore develop its own evaluation criteria.

Limitations

One of the main limitations is that there are knowledge gaps among architects and other key participants involved about POEs existence and use. Thus, it is no standard practice in the building development process which also results in a frequent lack of integration between the design, construction, and operation phases of a building. This could be due to academic researchers being the main developer and users of POE and because it is not taught in standard design education.

Moreover, the project budget often does not include POE because costs must be kept as low as possible. In addition, many other tools, “languages” and goals from different stakeholders are already used within one project, and including another approach might be excessive ^[8].

Another limitation is that the results of POE often are context-based, and the gained knowledge is therefore difficult to generalize. Further limitations make it difficult for the POE to be standard practice within the construction environment. It is often a discrete activity and independent from the continuing building management. This can result in the feedback not being linked back to the phases that were the most responsible for the success or failure of the project ^[3]. In addition, POE lacks agreed and reliable indicators which makes it difficult to implement it in the overall life cycle of a project. POE is mainly excluded from professional curricula. It is usually only done as a one-time exercise, shortly after the building is completed, which impedes continual improvement ^[8].

Besides, there is little incentive in the construction industry to change standard practices. Potentially, because applying POE could lead to negative outcomes e.g., indicating an underperformance of the project which could then hypothetically result in tenants moving out or demanding a lower rent ^[8].

Future improvements

To reduce above mentioned limitations, POE must be adapted to standard practice and its application needs must be simplified. Li et al. suggested developing POE from being a single case study to continuing investigations, from high-level to detailed, from research-oriented to occupants-oriented, from academia to industry, and from independent to integrated. This could be reached by e.g., starting with inexpensive and simple methods, carefully collecting, and developing indicators in cooperation with the building industry - such as common certification systems, or continuously feeding the results of occupant satisfaction surveys to a building automation control system ^[3]. However, this requires continuing research efforts and the development of a widely accepted implementation guideline.

POE’s applications reach further than for new buildings or one-time events only. A good fitting case study must be a continuing issue over the life of a building. Especially when the used space changes or the occupant's needs change. With POE, the loop between intention and reality can be closed, and it can improve the communication between stakeholders ^[8].

Combining POE with further tools could increase its use significantly. For example, User Experience (UX) is gaining importance within the building industry. UX is the concept to involve occupants and users already in the design process, reflecting on their needs and wishes. With POE those criteria can be assessed after a specific occupied time. Albeit, both POE and UX are case dependent there will always be information that can be useful for also adapting it in future projects. Lastly, if more architects, clients, and other members of the project team learn about how their buildings perform in use, their next buildings could do better in terms of energy use and meeting the consumer’s needs ^[7].

Annotated bibliography

Bill Bordass et al. developed the Probe series assessing the building performance in use. Part 1 is introducing the project of conducting several post-occupancy evaluations of commercial and public buildings. Part 2 is introducing the 16 buildings evaluated within the Probe series. Part 3 shows the comparison of the energy performances and carbon emissions of the assessed building. Part 4 reflects on the evaluation and gives advice on how to improve conditions for occupants and users.

1. Cohen, R., Standeven, M., Bordass, B., & Leaman, A. (2001). Assessing building performance in use 1: The Probe process. Building Research and Information, 29(2), 85–102. https://doi.org/10.1080/09613210010008018
2. Bordass, B., Cohen, R., Standeven, M., & Leaman, A. (2001). Assessing building performance in use 2: Technical performance of the Probe buildings. Building Research and Information, 29(2), 103–113. https://doi.org/10.1080/09613210010008027
3. Bordass, B., Cohen, R., Standeven, M., & Leaman, A. (2001). Assessing building performance in use 3: Energy performance of the Probe buildings. Building Research and Information, 29(2), 114–128. https://doi.org/10.1080/09613210010008036
4. Leaman, A., & Bordass, B. (2001). Assessing building performance in use 4: The Probe occupant surveys and their implications. Building Research and Information, 29(2), 129–143. https://doi.org/10.1080/09613210010008045

The Royal Institute of British Architects created a definitive model for the design and construction process of building. Next to the stages a project is going through, the guideline introduces post-occupancy evaluation and when and how to implement it.

1. Royal Institute of British Architects (RIBA). (2020). RIBA Plan of Work 2020 Overview. https://www.architecture.com/knowledge-and-resources/resources-landing-page/riba-plan-of-work

References

1. ↑ ^{1.0 1.1} Preiser, W. F. E. (1995). Post-occupancy evaluation: how to make buildings work better. Facilities, 13(11), 19–28. https://doi.org/10.1108/02632779510097787
2. ↑ Zimring, C. M., & Reizenstein, J. E. (1980). Post-Occupancy Evaluation. Environment and Behavior, 12(4), 429–450. https://doi.org/10.1177/0013916580124002
3. ↑ ^{3.0 3.1 3.2 3.3 3.4 3.5 3.6} Li, P., Froese, T. M., & Brager, G. (2018). Post-occupancy evaluation: State-of-the-art analysis and state-of-the-practice review. Building and Environment, 133, 187–202. https://doi.org/10.1016/j.buildenv.2018.02.024
4. ↑ ^{4.0 4.1 4.2 4.3} Ministry of education. (2016, February). Post-occupancy evaluation report. Stonefields School. https://www.education.govt.nz/assets/Documents/Primary-Secondary/Property/Design/Post-occupancy-evaluations/POE-Stonefields.pdf
5. ↑ ^{5.0 5.1 5.2} Managing Successful Projects with PRINCE2. (2017). Managing Successful Projects With Prince2. TSO.
6. ↑ The standard for project management. (2021). A Guide To the Project Management Body of Knowledge (pmbok® Guide) – Seventh Edition and the Standard for Project Management (english) (pp. xxvi, 67, 274 Seiten (unknown). Project Management Institute, Inc.
7. ↑ ^{7.0 7.1 7.2 7.3} McNeil, T. (n.d.). Post Occupancy Evaluation. Net Zero Carbon Guide. https://www.netzerocarbonguide.co.uk/guide/operation-and-in-use/post-occupancy-evaluation/summary
8. ↑ ^{8.0 8.1 8.2 8.3 8.4 8.5 8.6 8.7} Zimmerman, A., & Martin, M. (2001). Post-occupancy evaluation: Benefits and barriers. Building Research and Information, 29(2), 168–174. https://doi.org/10.1080/09613210010016857
9. ↑ Baird, G., Isaacs, N., Kernohan, D., McIndoe, G., George Baird & Victoria University of Wellington Staff. (1995, December 1). Building Evaluation Techniques. https://www.goodreads.com/book/show/2759399-building-evaluation-techniques
10. ↑ ^{10.0 10.1} Royal Institute of British Architects (RIBA). (2020, November 26). Post Occupancy Evaluation: an essential tool for the built environment. https://www.architecture.com/knowledge-and-resources/resources-landing-page/post-occupancy-evaluation-an-essential-tool-to-improve-the-built-environment
11. ↑ ^{11.0 11.1 11.2} Royal Institute of British Architects (RIBA). (2020). RIBA Plan of Work 2020 Overview. https://www.architecture.com/knowledge-and-resources/resources-landing-page/riba-plan-of-work