Escalate an estimate with price indices
Bring base-date rates forward to the midpoint of construction using published cost indices, so the number reflects when the money is really spent rather than the day the rate was set.
작동 방식, 단계별로
플랫폼 전반에 걸친 4단계 - 각 단계에서 무엇을 하는지, 그리고 왜 중요한지.
Set base and target dates
물가 지수Fix the base date of your rates and the target date to escalate to, usually the midpoint of the construction period where spend is heaviest.
이유: Escalating to the midpoint rather than the start or the end is the fair average across the spend curve. Getting these two dates right is most of the accuracy of the whole exercise.
Read the escalation factor
물가 지수Pick the index series that best matches the work - building, civils, or a trade-specific one - and read the factor between the base and target dates.
이유: The right series matters: labour, steel and energy do not move together. Choosing an index that fits the work is what makes the escalation credible rather than a blanket guess.
Apply it to the bill
내역서Apply the factor to the bill and read the escalated total next to the base figure, so the uplift is a line you can point at rather than a number folded into the rates.
이유: Showing the base and the escalated total side by side keeps the client's trust. It also lets you re-run the uplift cleanly if the start date slips again.
Record it in the basis
견적 근거Write the base date, the index series and the factor into the basis of estimate so anyone reading the price later knows exactly how it was escalated.
이유: An escalation nobody can reconstruct is an escalation nobody trusts. Recording the working is what turns a defensible method into an auditable one.