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No-one should be blamed. Looking back with the express purpose of finding mistakes is not something most professionals do voluntarily. And in construction, one of the most fragmented, budget-limited, fee-strapped, labour-based, high-risk industries there is, project post-mortems are understandably pretty rare.

However, industry's ignorance of how buildings perform is no longer excusable. The demand for better buildings is reaching a point where we must know how they really work, and for the resulting knowledge to be fed back into the design process.

The forces for change are obvious: Government is legislating against leaky and energy-inefficient buildings. Business is demanding greater productivity and efficiency. The most expensive corporate assets of all, the occupants, want buildings to be healthy, productive and pleasant places to work.

So the pressure is on the construction industry to devise standard methods of assessing the performance of buildings from cradle to grave. Whatever system of evaluation is devised, it will need to address not only physical issues like ventilation effectiveness, but also cover social, environmental and economic factors.

In June the Construction Industry Council hosted industry workshops to identify the framework for a standard approach to post-occupancy evaluation (poe). Around 40 practitioners in the field of poe were asked to assess four key areas where standards might be introduced: energy analysis, occupant analysis, design auditing, and building operability and cost-in-use.

Energy analysis
Energy analysis is a vital component of post-occupancy evaluation, particularly given that the energy intensity of office buildings has burgeoned by 60% over the last 10-15 years. However, in common with most other poe methods, energy analysis tools are not confined to the operation stage of a building. They can be applied at all stages of a building's life, preferably from briefing onwards.

But what exactly should we be measuring, and which methods of measurement are most appropriate?

Delegates discussed the merits of the various available energy assessment tools. The best candidates for championing as standard methods included the BREEAM suite of environmental assessment tools, BRE's ENVEST tool, and CIBSE's TM22: Energy Assessment and Reporting Methodology. Moreover, the task group identified a mass of energy consumption guidance and sustainability indicators that have become common currency in the construction industry.

Generally speaking though, the history of energy conservation is the triumph of hope over experience. There are simply too many barriers and not enough drivers for energy conservation to be taken seriously by building owners and operators.

For a start, there is no imperative on the energy utilities to provide detailed data on energy use. Compared to the detailed data freely available on telephone bills, energy bills are bereft of useful information. If the data was provided electronically, as an Excel spreadsheet for example, it would be easier for facilities managers to analyse.

"Once piece of software in a utility's billing mechanism would serve all of its customers" said BSRIA's Andrew Eastwell, "and it would be very efficient".

Businesses are often more motivated to waste energy than to save it. As ESD's Robert Cohen put it: "Clients think it's cheaper to leave pc monitors running overnight as it is thought to extend computer life and reduce network problems" he reported.

Delegates agreed the need for better links between clients, designers and contractors during the briefing process, and for a building's energy targets to be followed through construction to operation. However, there are a great many unknowns about how occupants use buildings, so if energy analysis tools are going to be used in future there is a clear need for them to be applied more in concert with the results from occupant surveys.

There was heated debate on whether or not energy legislation was useful (or even appropriate). Some felt that legislation was essential to combat the threat of embarrassment, others that the narrow legislative focus on CO2 emissions could inflict damage on business.

Another problem with energy legislation, said BAA's Brad Banfield, is that it is often attached to penalties. "A better approach to drive improvements might be for significant clients to adopt best practice performance levels"

"We need both inspiration and legislation" argued the PROBE team's Bill Bordass. "Design freedom has led people to design some very energy inefficient buildings, so there needs to be a clearer language for benchmarking.

"For the inspiration I would like to see the property industry and the designers getting together to create user pull. That way imagination could be injected into the process, rather than having to be pushed upwards by raising the legislative floor".

CIC Chairman Michael Dickson said that publicising energy consumption could inspire business to save energy, and that benchmarks would be an important part of the Clients Charter, recently launched by the Confederation of Construction Clients.

"We should be setting benchmarks, recognisable by the public, which would motivate building owners and users to achieve better standards" he said.

Occupant surveys
Analysing occupants' levels of satisfaction is fundamental to a evaluating the worth of a building, both in terms of its physical properties – space utilisation, lighting, ventilation etc – and in assessing how well a building meets an occupier's business objectives.

Occupancy surveys also need to be applicable to all stages of a building's development, from briefing through to occupation and beyond. Occupant surveys are currently regarded as "post-occupancy" activities, explained Santa Raymond, whereas in reality they are just as useful – if not more so – at the project briefing stage.

Currently there are as many survey tools as there are practitioners. Some methods are strongly empirical, others more subjective. Some concentrate on softer issues of space utilisation, others on harder issues such as the causes of building-related sickness.

The inherently subjective nature of polling human beings for their opinions means that extracting good data is fraught with difficulty. People can generate tremendous amounts of information, observed BRE's Gary Raw, but generally they are poorly calibrated and motivated by many things other than their physical surroundings.

The level of pay, the quality of management, and degree of job security for example can all exert a strong influence. So the vital component for any occupancy survey is the need to extract relevant and reliable building-related information and not get bogged down in management or behavioural detail.

A systematic, industry-agreed method of surveying occupants in a building was seen to be an important next step for the construction industry. The delegates debated at length whether there should be a single method or several, and whether such a methodology should be the preserve of independent consultants or publicly available. After all, what use is an industry standard if it isn't based on an open protocol?

The workshop delegates concluded that, rather than favour one method over all others, work needs to be done to identify the core characteristics of an occupancy questionnaire. This would cover the key questions, the scoring system, the recording of subjective data and anecdotal responses, and some rules on quality control.

Second, agreed survey methods should be licenced for use, with a condition of the licences that data and information is returned (confidentially, to prevent embarrassment) in order to support national benchmarks.

"It is not a question of control" explained Gary Raw, "but more one of moderation. We need to know what is going on and to check the data is valid" he added.

Delegates agreed that benchmarks will need to be created so that objective results from occupancy surveys – whether carried out by independent, accredited consultants or by building owners – can be entered into a database of similar buildings. This will give an indication of how buildings perform against particular types of buildings.

"Professional bodies like CIBSE, the RIBA and the BIFM could agree a basic set of standards for occupancy surveys, licence the methods and manage the data to build coherent benchmarks," proposed Adrian Leaman from ÐÇ¿Õ´«Ã½ Use Studies. "Eventually we would have enough data for meaningful comparisons to be made within different building sectors".

Sebastian Macmillan of the EPSRC agreed. "We need a better understanding of how different buildings work, and that demands a basic model for different building types" he said.

Design auditing
One of the trickiest and most intellectually demanding aspects of a building post-occupancy evaluation is analysing how close a building has got to the designer's original intention. A correct analysis presumes the assessor has a similar degree of knowledge as the original designer, as well as knowledge of the client brief, design specification and any changes made during the construction process.

The general view of the task group was that any evaluation of a design process should be less of a snapshot, and more of a continuous evaluation which would provide routes for feedback information to be injected at the appropriate time.

A formalised approach to post-occupancy evaluation would need to rely on some form of agreed auditing procedure; a technical design quality check in other words, which would identify all the important decisions, and when and why they were made.

Several research initiatives are attempting to devise a suitable methodology. Some, like the NHS Procure 21, have been developed to suit a particular sector. Others, such as the Sussex University/Construction Industry Council initiative on Design Quality Indicators are attempting to provide a method for measuring objective and subjective aspects of design quality, the results from which can then be compared against the design intent. A current BRE project: Design with Respect to the End User, is also trying to devise a joint briefing guide for clients and designers.

Delegates warned against the development of any industry-standard audit procedure which would rely on easily-found information rather than information needed in practice. Formalised procedures can also tend towards box-filling rather than context-specific design explanations which would be far more useful – preferably when written in a non-technical language that all stakeholders in a project can understand and agree.

ÐÇ¿Õ´«Ã½ operability and cost-in-use
This aspect of post-occupancy evaluation is probably the most business-focused of all. From a client's perspective, a post-occupancy evaluation is probably too late in the process said task-group delegates, who included noted architects Sir Andrew Derbyshire, Richard Fielden and Giles Oliver, along with poe specialist Ziona Strelitz.

However, design intentions tend to evolve. Rarely do clients know what they want at a fixed point. So any comparison between the design intent and the finished product has to acknowledge the stage the design reached when a decision was made.

In any case, a measure of a building's performance should not be purely cost-based, said delegates. Rather, cost indicators in use should examine the impact of the building on the entire business process.

To be useful the performance indicators should be aimed at facilities engineers, which means the tools of assessment need to be non-technical and capable of drawing information from all sectors of the business, not just facilities management. That means a major shift away from the more technical evaluations that currently characterise poe investigations.

It will also be important for business to enjoy quick and easy wins, and to be allowed to make incremental rather than dramatic improvements in sustainable building operation.

Actions for the future
The main consensus to emerge from the CIC workshop was the clear need for agreement on industry-standard methods for undertaking post-occupancy assessments. However, it was also agreed that the market is big enough and diverse enough to accommodate different methods and approaches.

Either way, poe faces a rocky road. There are considerable risks ahead, not least the perceived damage from bad news. Will the client look silly? Will the project manager lose face? Will angry clients reach for their lawyers? Will insurers block the investigations? As poe practitioner Ziona Streliz pointed out, the benefits of poe have to be linked to the risks of exposure.

"You also have to find the stakeholders in a building" urged ABS's Jim Ure, "and engage their interest."

As Jim and Santa Raymond both stressed, "post-occupancy evaluation" is a misnomer. It is also "pre-occupancy evaluation". The real value of poe is not what the data reveals about completed buildings, but in the repackaging of that data for use in a briefing and design process.

How, though, to make clients – particularly the small and occasional clients – aware that feedback information exists?

Enter the Confederation of Construction Clients (CCC) which has evolved to respond to this challenge. The CCC and its new chief executive Zara Lamont intends to cajole clients into to taking greater custody over the quality of buildings they procure.

Members of the CCC will be required to sign a Clients' Charter which, among other things, will commit them to adopt feedback as an essential part of their business management. They will also be required to collect and interpret data on the performance of their completed projects, and to share the results with the supply side.

The CCC, with the support of the Construction Industry Council, will be producing a feedback manual and supporting toolkit to help clients understand the practical requirements of feedback – how it improves performance, what techniques are available and what their use is likely to cost. An initial output of this work will also be a guide to post-occupancy evaluation, a step-by-step introduction to poe techniques.

"We should identify some common steps we can take...and give private sector clients the ability to benchmark [building] performance" concluded CIC chairman Michael Dickson "and for that we need a checklist of criteria for poe.

"ÐÇ¿Õ´«Ã½ owners can benchmark internally, but to assess their competitive position they will need common standards" he concluded.