Multi Criteria Analysis is a technical term for a process that people use every day to make decisions. The process supports decision making by clearly identifying and prioritising the factors that will be considered when making a decision.
Multi Criteria Analysis provided a tool for evaluating design and alignment options for the Roe Highway Extension. Using a sustainability assessment approach, the factors for the Roe Highway Extension project fell under three headings: Social, Environmental and Economic.
- Examples of social factors include the impact on heritage values and visual amenity.
- Examples of environment factors include the impact to wetlands, fauna and air quality.
- Examples of economic factors include the cost of construction and efficient freight and vehicle movement.
The criteria and their attributes were developed with input from community and stakeholders. South Metro Connect translated this information into weighted and measureable criteria for the design team. By applying the criteria to the various design options, we could easily identify those which were most appropriate.
A simplified example of Multi Criteria Analysis is shown below in relation to buying a car.
How was MCA used for the Roe Highway Extension Project?
South Metro Connect worked together with the community to establish the triple bottom line criteria that was then used to assess and select the most sustainable design option. This process involved an MCA criteria establishment workshop, a process of criteria consolidation and a final MCA process to analyse and select between multiple viable design options.
MCA Workshop - February 2010
On Friday 19 February, South Metro Connect held an MCA workshop at Willetton Sports Centre. The event was attended by 64 stakeholders and members of the community.
During the workshop, participants were asked to contribute to the listing of criteria for each of the three categories: environmental, social and economic. The lists were then collated and all workshop participants were asked to vote using a colour coded dot system. For each category, each participant was given 1 red dot (representing 3 votes), 1 yellow dot (representing 2 votes) and 10 blue or black dots (representing 1 vote each). The participants were asked to vote in three rounds for each of the three categories.
Preparation for the MCA Process of Options Selection
The team undertook a process to consolidate the results of the MCA Workshop. The results were collated into ranked and measurable criteria for use in the final MCA process of options selection.
Step One: Preliminary Data
The first step was to collate the raw data from the Community and Stakeholder Workshop. The preliminary data can be downloaded via the following links:
*Note: the raw data tables contain all the original material and vote counts from the workshop, plus a preliminary ranking. The rankings were changed when the consolidation process was completed.
Step Two: Consolidate and Re-rank the Criteria
The second step was to consolidate and re-rank the criteria. As part of this step, the team removed any overlap and duplication, and provided measurability for the designers and environmental scientists. We endeavoured to make this process as transparent as possible.
Step two of the consolidation process is as follows:
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Code the criteria as Soc1, Soc2, Soc3, etc., to allow traceability.
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Where necessary and appropriate, we combined criteria within a category (eg. combine Soc1 and Soc2) and add the votes. During the process of populating the framework the same criteria often appeared more than once. These criteria were joined together as one. For example, 'access' and 'connectivity' ultimately refer to the same thing and these criteria were combined.
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Where necessary and appropriate, we combined criteria across categories (eg. combine Soc1 and Env2) and collated the votes. For the MCA process to work, a criteria must only appear once and must not be repeated across different categories. For example, while 'noise' is both a social and environmental criteria, its primary location is social.
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Where necessary, we relocated criteria to another category (eg. Soc1 becomes a new Env criteria such as Env37) and relocated the votes to the new category. For the MCA process to work, a criteria must appear in its appropriate category and must not be repeated across different categories. For example, while 'noise' is both a social and environmental criteria, it should only appear in one category.
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Where necessary and appropriate, we split criteria into two or more new criteria (eg Soc1 becomes Soc5 and Soc6) and divided the votes evenly. If the attributes within a criteria are significantly different, they will be split into separate criteria and the votes were evenly distributed. At this stage, this does not seem to be a necessity.
The results of this step are provided below.
Step Three: Identify Measureable Aspects within the Consolidated Criteria
The third step was to work with the design team to identify the measurable aspects within the consolidated criteria. The results of this process are provided below:
Final MCA Workshop - June 2010 (Options Selection Workshop)
South Metro Connect would like to thank the community members and stakeholders who took part in the Multi Criteria Analysis (MCA) Workshop held on 29 June 2010.
The MCA Group, consisting of 17 community members and stakeholders, came together at the Retro Chef Function Centre in Bibra Lake to assess a number of viable design options for the central section of the proposed Roe Highway Extension between Bibra Drive and North Lake Road. The group had the task of selecting the most sustainable design option for the central section of the proposed highway according to the triple bottom line criteria established at the original MCA Workshop on 19 February 2010.
The group assessed four viable options during the MCA workshop:
- A northern alignment option developed by South Metro Connect.
- A southern alignment option developed by South Metro Connect.
- A northern alignment option derivative running along the Western Power line route.
- A full length bridge structure running along the northern alignment to allow for the penetration of light, fauna crossing opportunities and unconstrained surface water flow.
The MCA Group discussed and reviewed the four options and agreed that Option 3 – a northern alignment option derivative running along the Western Power line route, was the most sustainable option.
This option has since been reviewed by South Metro Connect and incorporated into the preferred concept design for Public Environmental Review.
Please click here to download a PDF version of the MCA workshop report.