Research and analysis

Monitoring and measuring research study: impact of MMC on the delivery of homes

Published 5 March 2021

Applies to England

1. Overview

Sector productivity is at the heart of the challenges facing the UK construction industry in the 21st century. UK industrial productivity has risen by some 25% and the automotive sector by around 45% over the last 20 years whilst construction productivity has virtually flat-lined.

The housing sector shares the broader construction industry challenges at a time when UK housebuilding requires a step-change in output.

1.1 Modern methods of construction

The adoption of modern technologies, products and processes for delivering the built environment, collectively Modern Methods of Construction (MMC), are widely reported to provide a partial solution to this challenge.

While there isn’t a precise definition of MMC, the term is often used collectively for a wide range of non-traditional building systems, which are categorised in the report Modern Methods of Construction working group: developing a definition framework’ (2019) from the MHCLG.

The House of Commons Select Committee report into Modern Methods of Construction (PDF, 369kb), published in July 2019, recognised that

a significant proportion of homes must be built using modern methods of construction (MMC) if we are to meet the target to deliver 300,000 homes annually.

Homes England is committed to supporting the delivery of homes in the UK to bridge the gap in housing need. They are also supportive of the increased use of MMC in delivering these homes, believing it may help address limited productivity gains in the construction industry.

However, the evidence base supporting the benefits of MMC use is limited. To address this gap, Homes England has commissioned a significant research programme to evidence the impact of MMC deployment within the housing sector across 8 pilot sites, totalling approximately 1800 homes.

It is hoped that the evidence of the benefits of MMC use will provide greater confidence to the industry, investors, insurers and customers to support its use across the sector.

The key drivers for this research commission are to:

• establish a robust data set on the construction of homes utilising MMC
• provide the housing industry with confidence in the use of MMC to deliver homes based on a verified body of data.
• establish a benchmark approach to collecting data on MMC homes.

Whilst acknowledging the importance of the design and planning phases, the research will focus primarily on the effects of MMC use during the delivery phases of the development processes.

2. The developer teams

As part of this research’s commitment, Homes England is working with 8 developer teams to deliver homes using MMC systems at different scales. Each developer team has, in turn, committed to supporting the research team in data collection to monitor and measure the performance of MMC on each of their sites.

2.1 Constraints

This study is looking to compare different approaches to delivering homes using MMC, and as such, the project does not include a site following traditional construction methods.

Therefore, the research is constrained by this limitation and will focus on the comparative analysis of the different approaches to delivering homes using MMC. Where possible, the research team will make comparisons with traditional construction methods.

3. The research team and programme

Homes England has commissioned Atkins/F&G to deliver this project, leading a combined research team, bringing together the best academic, construction and manufacturing industry knowledge to respond to this challenge.

Atkins/F&G provide senior professionally qualified technical capability, experience in leading and delivering critical national infrastructure in the context of modern methods of construction, and design for manufacture and assembly.

University College London (UCL) is delivering essential expertise in construction economics and ensuring the data used in measurement techniques and statistics are robust.

Building Research Establishment (BRE) provides an essential role in accessing existing data, supporting the utilisation of their technology databases and defining new metrics.

This report presents a summary of the work and outcomes from this first stage.

4. Project scope

One of the main drivers for Homes England in commissioning this study is to help build consistency in measuring the impact of MMC across the sector rather than unnecessarily reinventing an altogether new approach.

The first stage of the research commission focussed on ensuring that the areas being explored were relevant, appropriate, and aligned with previous work in the sector, namely, the Construction Industry Research and Information Association’s Methodology for quantifying the benefits of offsite construction, and the Advanced Industrialised Methods for the Construction of Homes (AIMCH) project.

This section briefly describes the process adopted to define the research project’s scope. It explains how the themes, metrics, and data points were defined, creating a robust structure to answer the questions posed by Homes England.

4.1 Project themes

Through industry-wide consultation, and with reference to the work of the Construction Leadership Council’s (CLC) Smart Construction Dashboard for housing, Homes England initially proposed 13 themes to address the drivers for the study.

The research team compared these proposed themes against recent academic literature, and those adopted by the CLC, CIRIA and the AIMCH to ascertain the completeness of the proposed themes for the study.

The team established that there is broad alignment across the key themes of time, cost, quality, safety, productivity and waste reduction. However, the AIMCH and CIRIA reports both capture predictability as a theme which is not included in the CLC dashboard. This was felt to be important and included in the revised set of themes.

The team also incorporated social value and wellbeing as themes in the study at a high-level. These are both areas under review by the CLC for inclusion in the dashboard.

Finally, due to the influence that a site context can have on the implementation of MMC, the team introduced a theme to develop a detailed description of the site and context.

Table 1 includes a complete list of the themes to be explored in this research project.

Table 1: Summary of themes

	Theme	Description
0	Description of site and contexts	Fact-based narrative reporting capturing detailed information about the site, phasing, tenure, MMC type, dwelling types.
1	Pace of build	A review of the construction phase (days on site), factory phase (days off site), considering time in transit for MMC elements and predictability of deliveries.
2	Cost of build	Complete cost of build accounting for capital cost, preliminaries cost, site labour costs, predictability of cost, as well as costs associated with risks. In additional, the spend profile for a project will be captured to make an estimate of the (opportunity) costs of finance for the project.
3	Labour productivity	Assessment of the value of labour hours worked on the sub-assembly and site using record of trades on site.
4	Planning issues	Assessment on whether securing planning consent for the MMC scheme faced any hurdles that a traditional build would not.
5	Pre-manufactured value	The value that is created as a result of completing work away from the site.
6	Safety performance	Number of people injured over a year for each million hours worked by a group of employees or workers.
7	Levels of construction wastage	Record of the embodied carbon per dwelling, construction phase waste, as well as construction and factory energy and water usage.
8	Construction logistics	Understanding the relationship between the developer, the MMC manufacturer and the contractor who integrates offsite elements.
9	Delivery performance: ‘quality rating’	Record of post completion defects and pre-completion re-work.
10	Energy efficiency performance	Average Energy Efficiency and Environmental Impact ratings and EPC band per dwelling type at design stage.
11	Sales performance	Combination of narrative based feedback and factual reporting on mortgage, insurance and warranty provision
12	Life cycle	Adaptability, maintenance cost and end of life assessment for a development.
13	Economic rationale	Incremental cost and benefits of MMC use identified on projects.
14	Social value	Impacts from building works on the local community.
15	Wellbeing	Theme related to the well being of the residents in a dwelling.

4.2 Metrics

Within each of the themes, Homes England proposed a range of metrics, building on the CLC Smart Construction Dashboard.

The research team undertook a desktop review and assessment of the proposed metrics before comparing them with the recent industry reports to confirm their completeness.

This review highlighted several definitional challenges to be addressed, and new metrics that could improve the coherence and comparability of the Homes England data set. As well as the metrics related to predictability described above, 2 significant areas of research activity were recommended for inclusion in the study.

Factory-based activity

The metrics proposed by Homes England focused only on on-site delivery. Therefore, factory-based data will be collected in some metric categories to ensure that the removal of activity and impacts from site do not simply get transferred to the factory setting. The research team recognise that there may be challenges in gathering this data as it depends on the relationship between the developer and factory.

User satisfaction and maintenance

Despite the research focus on the delivery stage of construction, the UK’s post-war experience of off-site development is one of defective dwellings and large repair bills.

Given this historical precedent, satisfaction and maintenance represent important areas for exploration. While buyer perceptions of quality can be tested at the point of sale, the build’s quality can only really be validated once the homes have been lived in for some time.

However, post-occupancy evaluations were initially excluded from this study, as developers are unable to guarantee access to the dwellings. The research team has agreed with Homes England that the work scope be extended to include high-level feedback surveys to gather initial user experiences in the homes. This will provide high-level qualitative feedback but the research team has highlighted the need to expand the exploration of this theme beyond the commission of this study.

A complete list of the metrics being explored in this study are included in Table 2. Whilst each metric’s descriptions in 2 is brief, a defined boundary and scope support each. Further, where the scope, boundary, or calculation of the metric differs from those used in the CLC, CIRIA and AIMCH work, the research team have ensured that comparable figures can be presented.

Table 2: Complete schedule of proposed metrics for the Homes England study

	Theme	Metric
0	Description of the site in context	Fact-based narrative reporting
1A	Pace of build	Days on site (construction phase)
1B		Time spent in factory (days off-site)
1C		Travelling time from factory to site
1D		Predictability of delivery (unit-level data)
2A	Cost of build	Capital cost
2B		Preliminaries cost
2C		Site labour cost
2D		Predictability of costs (unit-level data)
2E		Costs of risk
2F		Financing costs
3A	Labour productivity	Value of labour hours worked (site)
3B		Value of labour hours worked (sub-assembly)
3C		Trades on site
4	Planning issues	Fact-based narrative reporting
5	Pre-manufactured value	Pre-manufactured value
6A	Safety performance	Site-based injuries as reported per RIDDOR
6B		Factory-based injuries as reported per RIDDOR
7A	Levels of construction waste	Embodied carbon (Design: per dwelling type)
7B		Total volume of construction phase waste produced
7C		Construction and factory energy usage
7D		Construction and factory water usage
8	Construction logistics	Fact-based narrative reporting
9A	Delivery performance: ‘quality rating’	% of total build costs that are incurred pre-completion
9B		Number of post-completion defects
9C		Costs of pre-completion work
10	Energy efficiency performance	Average SAP/EPC rating per dwelling type
11	Sales performance	Combination of narrative-based feedback and factual reporting on mortgage, insurance and warranty provision
12A	Life cycle	Adaptability - DfD/A plan prepared in accordance with ISO 20887:2020
12B		Maintenance Costs - Expected maintenance costs of the unit
12C		End of life - DfD/A plan prepared in accordance with ISO 20887:2020
13	Economic rationale	Benefit-cost profile
14A	Social value	Proportion of units assessed under social value network
14B		Local disruption – Vehicle movements
14C		Local disruption – Air quality
14D		Local disruption - Noise
15	Wellbeing	Proportion of units assessed under a recognised wellness framework

4.3 Data points

In developing the schedule of metrics, it became evident that there was overlap between the metrics in their use of data. Further, it was not certain that the developers would routinely report on the KPIs as defined.

Accordingly, a decision was taken to break down the metrics into a series of 40+ unique data points that supported the calculation of all the metrics. Isolating individual data points in this way makes the data request from the developers more focused, reducing duplication and ensuring consistency between metrics and comparability across data sets.

This metric breakdown also means that metrics can be converted for use with other metric sets where required.

For each data point, a common scope, boundary, and unit of analysis were defined to ensure consistency of reporting across the 8 sites. This information has been captured in a series of metric factsheets available to each developer team as part of each site’s supporting information.

Figure 1: Relationship between themes, metrics and data points

5. Data collection

Across the construction sector, methods used to collect data vary in consistency and quality. Building upon industry reports including those from the CLC, AIMCH and CIRIA, the research team analysed the impact of a range of practical and organisational challenges known to prevent the collection of robust datasets needed for subsequent in-depth analysis.

These included:

• developers having limited and regular access to the raw data
• known variability in measurement methods used across different sites
• level of consistency and quality of data degrading over time
• allocation of resources and developer engagement to collect data
• awareness and access to new data capture tools beyond traditional approaches
• unique project constraints or abnormal influences that prevent data collection
• inter-related issues to share data across different organisations and into the broader supply chain

Given the novelty of some of the proposed metrics and the need to compare performance across different sites, the research team started by evaluating each developer’s ability to collect data that meets the identified 15 research themes’ requirements.

This provided an opportunity to determine a set of ‘feasible’ protocols that help overcome individual developer issues whilst ensuring a common approach to benchmarking.

Engaging with developers to highlight data collection benefits has provided further opportunities to introduce pragmatic approaches to improve consistency that complemented current practice.

5.1 Improving data collection and quality

The team identified various individual challenges in collecting data suitable for long-term benchmarking studies through engagement with the participating developers.

To address these issues the team introduced a Data Quality Framework (DQF). This framework encourages the regular self-assessment of the data captured by developers. Acting as a feedback mechanism between the research team and developers, it is expected that a DQF will encourage the use of consistent measurement practices and increase confidence in the accuracy of the captured data.

Design principles for a DQF specific to the Homes England metrics were also outlined; presenting a workflow solution that can adjust to developers’ different abilities to capture data yet offer a structure for continuous improvement towards standardisation across projects.

5.2 Digital tools to support data collection

The most common practice for data collection within the developer teams was manual data entry and capture. Whilst some developers are now using digital construction management tools, these methods provide routes to collecting data that only meet the requirements for a smaller sub-set of the 15 research themes. Given the potential for human error and the need to store data securely consistently over a long time, these practices represent a significant risk to data quality.

The research team has performed a functionality survey to evaluate digital tool kits’ availability to reduce the burden of data collection and standardisation of practice across the 15 research themes. It was found that whilst tools such as BRE SMARTWaste cover a number of the research themes, there is no single platform that can capture all of the data.

For this research, the study has developed a custom data collection platform based on Atkins Assist. This platform allows for collecting all the data points required for the study and works through a simple web-based console.

This custom data collection platform can then be linked to existing tools such as BRE SMARTWaste that the developer teams are using to prevent duplication in data collection. Quality assurance and checking functions are also available via the system’s secondary tools to ensure the submission is complete and consistent.

Using this platform is expected to offer:

• flexibility to design data entry processes specific to the project requirements
• solutions to individual data collection challenges
• digitally secure datasets that are comparable across each site

6. Project progress

The research team have made good progress with the study despite the impact of the global pandemic on both the global workforce and specifically the construction sector and UK commerce.

The team have undertaken a thorough review and validation of the research metrics and methodology. Their recommendations for the additional themes and metrics as well as the proposed data collection methodology have been presented and agreed with Homes England.

As well as testing the final metrics and data collection methods with the industry, the team have engaged closely with the developer teams involved in the study. The team are now ready to move forward with increased pace and are moving into Service 2 and 3 of the project, which focuses primarily on data collection.

Undertaking an initial review with a smaller group to validate the proposed approach proposed, the research team is now working through the detailed methodology with the specific developer teams and their supply chains to ensure the project’s data collection phase runs as smoothly as possible.

Going forward, the data collection across the 8 sites will take place in a staggered approach that reflects the timings of construction programmes on each site. The research team will be focused on making this process as streamlined as possible to ensure a robust, consistent and verifiable dataset at the end of the project. The team have successfully commenced project-specific data capture on one site to date.

An annual report on findings to date, produced in coordination with the Homes England Technical team, will be made available to the wider construction industry to support Homes England’s commitment to knowledge sharing in this very important growth area for the industry as a whole.