This section gives an overview of the key variables that have been included and excluded from this model. Whilst it is clear that all of these variables play a part in the resource size of a PMO we have not included them in this model because of the subjectivity in measurement. Our recommendation is that you increase/decrease contingency according to the secondary variable levers.

TABLE 3 - PMO Considerations INCLUDED in Estimating Model

Consideration	Variable	Description
Programme Headcount	Headcount	The higher the supported headcount the greater administration overhead for timesheet creation, report generation, process governance and compliance management.
Functional Complexity	High, Medium, Low (by function)	The required complexity of the PMO function will obviously contribute to the necessary support headcount e.g. A simplistic time-sheeting and high-level Financial reporting PMO will clearly need less headcount than a full Quality, Financial, Resource, Procurement, Scope, Planning, Time, Risk/Issue management function.
Enabling Technology	High, Medium, Low	The wider application of toolset automation significantly reduces administration. Options include (from low to high automation/enablement): (1) bespoke or repurposed Excel templates, (2) MS Project/Project Professional or equivalent being used in conjunction with Excel, (3) MS Project Server, EPM, Niku, Mercury ITG for the range of simple automation to full process and lifecycle automation. Clearly these factors will be largely dependant on the budget/skills available for implementation.

TABLE 4 - PMO Considerations EXCLUDED from Estimating Model

Consideration	Variable	Description
Strategic Delivery Model (SDM)	Locations	The higher the number of locations involved the more resource is required centrally and locally. Split working attracts additional complexity such as time (differing time zones), cultural (differing 'ways of working'), communication (differing languages and using only e-mail, messenger, telephone etc)
Management Support	High, Medium, Low	Support from the Senior Executive/Management team, simplicity of reporting lines and clarity of programme vision (inconsistent vision will lead to rework, significant ad-hoc reporting and reduced decision-support) contribute to a reduced support overhead.
Programme Management Maturity	High, Medium, Low	Initial process/policy/contract/template maturity all provide an environment within which activities can be supported more efficiently. These processes may exist in other business areas such as HR, Finance, Contract Management, General IT etc but can be repurposed for the management of the programme.
PMO Resource Capability / Seniority	High, Medium, Low	Greater experience and team skills correlate to lower time for PMO functional execution and decision-making. The more capable and experienced PM team members are, the more efficiently PM can be setup and operated.
Engagement Workforce Capability	High, Medium, Low	The experience of normal engagement staff in working with timesheeting, quality assurance, planning, financial reporting etc will reduce the amount of time a PMO will spend doing ongoing training and awareness sessions and general support.
Programme Delivery Complexity	High, Medium, Low	The (1) higher the number of organisational/delivery entities involved, (2) higher the risk (which drives volatility of PMO requirements), (3) governance model (is the PMO autonomous for a specific project or does it exist within a matrix of conjoined PMOs) the more PM resources will be required. In many instances complex programmes will devolve responsibility for some PMO activities to workstreams and maintain the strategic vision, PMO engagement plans, standardised processes, templates and reports centrally.
Diversity of Programme Scope	High, Medium, Low	Diversity of scope will drive different requirements for reporting and governance mechanisms e.g. EV application, status reporting, Risk and Issue management and metrics requirements (which will be different for an outsourced Service Delivery function and a conventional programme of project work.
Phase of PMO Lifecycle	Set-up, Operation	The set-up phase of a PMO requires more resource to successfully develop, implement and bed down processes/templates/toolsets. Once the PMO is operational and these assets have reached maturity there is a reduced support requirement for PMO resources.

The next part of the process is inclusion of the defined variables into the mathematical model...