Function Analysis and FAST Diagramming

Principles of Function Analysis The analytical technique that gives value management its power. It is used to understand the functions that a design solution must perform.  Once the functions are understood, a solution can be developed without bias or presumptions.  Function analysis examines what something does NOT what something is to avoid preconceptions and stimulate innovation. The best design solutions are those which reflect the client's values to the greatest extent or in later VM workshops, the solution which fulfils key design parameters (e.g. reducing cost) Functions analysis during later VM workshops would be used to examine alternatives for providing a required function, it cannot be assured that the alternative will provide the sought functionality more effectively.  If used correctly, function analysis will discourage designers from recreating previous solutions without confirming its appropriateness. Function analysis can also be used to inform the development of alternative ways of providing sought functionality. Functionality is usually related to cost to give a basic expression of value; however, it provides an inadequate expression of value as it does not take the client's values into account. Function analysis is constrained in it's ability to fully express the nature of value but remains an effective way of analysing what the client requires from the design solution.   

Expressing Functions: Verb-Noun Function StatementsFunction analysis defines functions using: A single active verb and a single descriptive noun. The verb asserts a condition. The noun defines. Prevents preconceptions about what the solution should be. Providing clarity about what the project must do, ensures 'all cost is for function' (Miles' central principle of function analysis) A design feature which does not enable all the sought functionality, is simply adding cost and is reducing value and should not be present. Due to difficulty of describing a function using a single verb/noun, some leeway is acceptable where complex functions require the use of more words. This practice should be minimised as deviance from single verb/noun format risks biasing the designers towards a particular solution, reducing their ability to seek a solution which reflects the client's values.  Examples - Transmit light, maximise insulation, minimise vibration... Function TypesNot all functions are considered equal in a function analysis. A functional hierarchy is formed to represent this.  Basic Function - Defines the purpose of the solution, often in the form of the project's mission statement. If the basic function isn't fulfilled, the design proposal is a failure. Primary Functions - The basic function is enabled by several primary functions. A primary function can exist in it's own right. Secondary Functions - Each primary function is often enabled by one or a few secondary functions. Tertiary Functions - Some secondary functions may require tertiary functions to enable them, but suggests a lack of clarity or consensus among stakeholders in the function analysis. Performing Function AnalysisFunction analysis requires: A method of eliciting functions. A method of reviewing functions. A method of organising and understanding functions. Function analysis is a brainstorming activity involving a 2-step process: First elicit possible functions, generally via a brainstorming exercise.  Then review and organise functions to 'make-sense' in a clear structure using FAST diagramming.  Identifying Functions Each participant is given sticky notes. The facilitator explains the verb-noun elicitation format. The project problem is quickly reviewed to clarify its scope. Participants are asked to individually note down all the functions they think the building needs to provide (in 15 minutes) It is about quantity, not quality and are encouraged to not critique or filter their answers. The facilitator then gathers the post-it notes and shuffle them into a randomly-ordered pile before undertaking the next stage which is Affinity Diagramming.  Affinity Diagramming Process of stakeholders working together to group similar functions. The post-it note at the top of the random pile is placed in the centre of the work surface.  The facilitator takes the next post-it note and reads aloud the function to ask the stakeholders how similar/dissimilar it is to the function on the surface. Alternatively, stakeholders can hold on to their post-its and position it themselves; however, this approach limits the sense-making as some stakeholders will be unaware of discussions others have had.  If dissimilar, it is positioned further away; if similar, it is positioned close by; if exactly the same, it is placed on top.  Stakeholders should be encouraged to stand up as this stimulates engagement.  Once the functions have been placed and discussed, obvious clusters of related suggestions will emerge, with those closer sharing a stronger conceptual association.  Discussions build common understanding of the logic supporting the groups. 'Silence means yes' rule applies. Before finishing, the facilitator asks stakeholders to review the emerging clusters and agree they are happy they make sense and if not, to move post-it notes and explain their rationale for doing so.  Once all stakeholders are happy with the arrangement, the affinity diagramming exercise concludes by the stakeholders discussing, agreeing and assigning meaning to each cluster and a name using a verb-noun pairing if possible to ensure they all share a common understanding of the clusters.  The verb-noun format provides the functions in the required format for the next stage of the process, FAST Diagramming.  Principles of F.A.S.T. Diagramming Many different types. This module focuses on the Customer F.A.S.T. diagram format. A F.A.S.T. diagram organises the functions identified by function analysis into the primary, secondary and tertiary functions. Essentially, FAST diagramming provides a simple representation of the client's functional expectations and stimulates social construction of common understanding between stakeholders.  It expresses requirements in purely functional terms to allow creative problem solving. A FAST Diagram is self-validating and can be read in either direction.  Lower-order functions are positioned progressively right along the horizontal 'How?' axis. Higher-order functions are positioned progressively left along the horizontal 'Why?' axis. The vertical positioning of primary functions along the vertical needs vs. wants axis determines their importance. The positioning of secondary functions to a primary function can tell designers whether the stakeholders consider those functions equally important in supporting the primary function.  Components of Customer F.A.S.T. Diagrams Why? vs. How? axis. Needs vs. Wants axis Scope lines. Functions organised into a hierarchy comprising of: one basic function, several primary functions, several secondary functions and a resource constraint line. Why? vs. How? Axis The horizontal axis. Explains the relationship between the functions the project must perform by establishing a hierarchical relationship of functions. Functions to the left are supported/facilitated/enabled by functions to the right.  If completed correctly, the diagram can be read in either direction along the axis - it is self-validating.  Needs vs. Wants This is the vertical axis. Designers need to know the stakeholders' priorities. Stakeholders must determine which functions are needed and which are wanted. Incorporating every function is unlikely as projects have finite resources (e.g. time and money) Primary functions are ordered vertically by their importance to the stakeholders. Functions positioned towards the top of the diagram are needed and those towards the bottom are wanted. Positioning the functions begins to expose stakeholders' priorities which are a consequence of their values. Scope Lines Always 2 scope lines. They define the content of the problem to be solved. Anything left of the left scope line is the definition of the problem. Anything to the right of the right scope line is the solution (or part of) to the problem.

The Basic Function Describes the overall function that the project must provide. If the basic function is not performed, the project outcome will fail. Sometimes written as a short mission statement. Must be negotiated and agreed by the stakeholder when preparing the F.A.S.T. Diagram Often easiest to define the basic function after all other functions have been organised. Primary Functions Are the main functions that the project must perform. They collectively describe the functionality required from the whole project solution. Individually, each describes the functionality required from a key component of the project. Secondary Functions Required to support the primary functions. A primary function can be supported by several, single or no secondary functions. Tertiary functions might also be required. Resource Constraint Line Is a horizontal line added to the diagram last. Requires stakeholders to distinguish between the functions that are needed and those that are wanted.  Stakeholders must consider available resources and position the line accordingly. Difficult to position meaningfully and may just represent functions stakeholders' are willing to sacrifice.  A design which does not provide a needed function will be considered a failure by stakeholders.  A design which does not provide all wanted functions will likely still be supported by stakeholders if all needed functions are provided, although an element of disappointment  will exist.  Compiling the F.A.S.T. Diagram Process is led by the facilitator and begins with a blank surface on which the facilitator draws the necessary scope lines.  The functional groups from the affinity diagram are written on new post-it notes which are used to organise the FAST diagram. The facilitator picks a random function and places it in the centre of the diagram. Another function is positioned by the facilitator Firstly, it's horizontal position is determined by asking stakeholders if it supports the basic function or another function which determines whether it is a primary, secondary or tertiary function.  This process is carried out until the pile of functions are exhausted and each function is classified as either primary, secondary or tertiary. The vertical position is then determined by asking stakeholders what function between adjacent primary functions most needed.  Once stakeholders are happy with the vertical arrangement of primary functions, the resource constraint line is positioned. The stakeholders are asked to consider which primary functions, if any, the solution could fail to provide without losing their support.  The functions positioned below the resource constraint line are those which designers could sacrifice if resources became constrained later in a project.  The facilitator then may ask the stakeholders to weight the secondary functions based upon a simple agreed judgement, which is usually expressed as a ratio (50:50) in their importance in supporting the related primary function. Tertiary functions are not weighted as the additional insight would be minimal.  Once positioned of all functions are agreed, the facilitator will draw the lines to connect the hierarchical structure to show the relationships that have emerged.  The FAST Diagram exercise concludes with stakeholders agreeing on the basic function which explains the purpose that all the other functions are required to fulfil. This is left until last as stakeholders need to understand the interrelationship between the other functions to define the overall purpose of the building.  The basic function could be in the verb-noun format; however, this is often difficult to agree so a short mission statement is often negotiated and agreed by stakeholders as the basic function.  Verifying the Diagram The logic of the diagram can be checked by reading it in both directions (left to right & right to left) Higher-order functions (left) must be supported by any subordinate lower-order functions (right). Lower-order functions (right) must support their superordinate higher-order functions (left). Process is led by the facilitator. Stakeholders are asked to read the diagram from left to right and then right to left.  Summary of Stages of FAST DiagrammingDuring VM1: Brainstorm functions. Sort & negotiate functions. Compile the diagram Verify the diagram Concept Design is Developed In-Between. During VM2:Revise the diagram in light of design proposals.

page 1

page 2