Definition

In an APC context, forecasting techniques are the structured methods used by a business to produce estimates of future outcomes. They range from data-driven quantitative approaches to judgement-based qualitative methods, and most surveying practices use a combination. The HM Treasury Green Book (2022) is relevant whenever a firm is assessing a significant investment or service change.

Why this matters for Business Planning

  • Level 1 knowledge: you must be able to name at least four forecasting techniques and describe when each is most appropriate.
  • Forecasting is the analytical backbone of every business plan: without it, revenue targets and staffing decisions are guesswork.
  • Assessors expect candidates to link forecasting to the firm's planning cycle, budget, and SMART objectives.
  • Candidates who have contributed to their firm's annual budget or fee forecast will have ready-made examples to draw on in their interview.

Key principles

Trend analysis and moving averages

Trend analysis plots historical data over time and projects that trend into the future. A surveying firm might chart monthly instruction volumes over three years and use the trend line to project the next 12 months. A moving average smooths out short-term fluctuations by averaging data over a rolling window. Both techniques are most reliable when underlying drivers of demand are stable; they are poor predictors of sudden market shifts.

Regression analysis

Regression analysis models the statistical relationship between a dependent variable — such as residential valuation instructions — and one or more independent variables, such as mortgage approvals. The resulting equation produces a forecast whenever the independent variable is known or can itself be predicted. Regression is more powerful than simple trend analysis because it explicitly models the drivers of demand.

Delphi method and expert judgement

The Delphi method is a structured qualitative approach in which a panel of experts independently provides estimates, receives anonymised feedback, and revises their estimates through multiple rounds until a consensus emerges. It is particularly useful when there is no reliable historical data — for example, when forecasting demand for a new service line. Expert judgement in a less structured form is the primary input to most surveying firms' fee forecasts.

Scenario planning

Scenario planning develops several plausible futures — a base case, an optimistic case, and a downside case — and assesses the firm's resilience under each. It is most useful for strategic planning over a three- to five-year horizon, where uncertainty is high. A well-designed scenario plan identifies the trigger conditions that would cause the firm to switch strategy — for example, pausing recruitment if instruction volumes fall 20 per cent below the base case.

Relevant RICS guidance and legislation

  • RICS Rules of Conduct (effective 2 February 2022) — the firm obligations require regulated firms to be financially sound; robust forecasting is part of the management discipline that supports this.
  • HM Treasury Green Book (2022) — the authoritative UK framework for investment appraisal; its guidance on optimism bias is particularly relevant, as organisations systematically overestimate benefits and underestimate costs when producing forecasts.
  • Companies Act 2006 — directors who produce materially misleading financial projections for external parties may face liability; forecasts shared with lenders or investors should be based on reasonable assumptions and clearly caveated.

Ethics and Rules of Conduct angle

The HM Treasury Green Book identifies optimism bias as a systematic tendency to produce overly optimistic forecasts — particularly acute in professional services where partners have a vested interest in projecting high revenue. Rule 1 of the RICS Rules of Conduct (honesty and integrity) requires members to be honest in all professional work, including internal management. A manager who knowingly presents an inflated forecast to secure board approval is behaving dishonestly, even if no client is directly affected.

APC-style Q&As

Q (Level 1)Name four forecasting techniques used in business management.

Trend analysis, moving averages, regression analysis, and the Delphi method. Other techniques include exponential smoothing, scenario planning, and market surveys. Most businesses use a combination of quantitative and qualitative methods.

Q (Level 1)What is the difference between a quantitative and a qualitative forecasting technique?

A quantitative technique uses numerical data and statistical methods, such as trend analysis or regression, to produce a forecast. A qualitative technique relies on structured expert opinion, such as the Delphi method, when data is limited or unreliable. Both have a place in a well-designed forecasting process.

Q (Level 2)Why might a moving average underestimate demand during a period of rapid market growth?

A moving average gives equal weight to each period in the window, so in a rapidly growing market the early (lower) periods pull the average below the current trajectory. Exponential smoothing addresses this by giving more weight to recent periods. However, both methods struggle in genuinely discontinuous markets where past patterns no longer predict future demand.

Q (Level 2)When would you use scenario planning rather than a single-point forecast?

Scenario planning is most appropriate when uncertainty around key assumptions is high — for example, when planning over a three- to five-year horizon, entering a new market, or when a significant external event could materially alter demand. A single-point forecast in these circumstances creates false confidence; scenario planning makes explicit the conditions under which different strategies should be adopted.

Q (Level 3)Your firm's residential valuation team has produced a fee forecast showing 30 per cent growth in the next financial year. The managing partner is sceptical. How would you quality-assure the forecast?

I would start by unpacking the assumptions behind the 30 per cent growth: how much is driven by volume growth and how much by fee rate increases? I would test the volume assumption against external data — HMRC transaction counts and mortgage approval trends — to check whether the market is expected to grow at that rate. I would apply the HM Treasury Green Book's optimism bias adjustment as a sense-check, then model a downside scenario based on a 10 per cent market contraction to identify what cost adjustments would be needed. The revised forecast, with documented assumptions and a range of outcomes, would be presented to the managing partner for approval.