AACE CCT common mistakes
AACE CCT · Understand the traps and how to avoid them.
Adding contingency as one flat percentage (e.g., 10%) to every estimate regardless of the estimate class, scope definition, or identified risk exposure.
Candidates memorize a single 'standard' contingency number from templates or sample problems and never connect contingency to the estimate classification and risk analysis that justify it, so they answer class-specific questions with a generic figure.
What to do instead
Build a one-page table mapping AACE estimate classes (5 through 1) to their expected accuracy ranges and typical contingency bands, then practice justifying each contingency value from a short risk register or range analysis rather than a percentage rule of thumb.
Applying total escalation for the full project duration to the whole estimate instead of escalating to the midpoint of construction (or to the correct expenditure point).
Candidates treat escalation as a simple multiplier on today's cost base and overlook that money is spent over time, so mid-period compounding and the difference between base-date and mid-point dollars get collapsed into one wrong number.
What to do instead
Work three or four practice problems where the base date, construction midpoint, and escalation rate are all stated, and write out the compounding formula and the time reference explicitly before computing.
Pricing labour at the bare wage rate, omitting labour burden, overtime premiums, per-diem, and productivity loss factors when building a detailed estimate.
The wage rate is the most visible number on the page, so candidates anchor on it and forget that fully burdened labour cost and productivity adjustments usually dominate the labour line item.
What to do instead
Drill a standard build-up: base wage, then statutory and fringe burden as a percentage, then overtime and shift premiums, then a productivity adjustment; recompute a small crew estimate end-to-end until the sequence is automatic.
Reporting total float where the question asks for free float, or reading float from the wrong activity after a forward and backward pass.
The two floats are computed from the same network, so under time pressure candidates grab whichever number they calculated last instead of checking which activity the question names.
What to do instead
Do hand CPM calculations on a five- to seven-activity network, labelling ES, EF, LS, LF, total float, and free float in separate columns for every activity, and confirm the answer against each activity's immediate successors before selecting an option.
Treating activity durations as calendar days and computing schedule dates arithmetically without applying the project calendar, holidays, or weather days.
Textbook problems often use round numbers, so candidates carry a 7-day arithmetic habit into questions that specify a 5-day workweek or a weather allowance.
What to do instead
On every duration question, first state the calendar in use and convert durations to working days, then count forward on the calendar; practice with at least one problem that spans a holiday and one that includes weather downtime.
Confusing crashing with fast-tracking and misapplying the cost slope, or assuming the critical path is fixed after a schedule update.
Both are schedule compression techniques and both shorten the project, so candidates blur them, and they also assume the critical path identified at baseline survives progress updates and logic changes.
What to do instead
Memorize the pair as a contrast table (cost versus risk, logic change versus resource addition), practice selecting the lowest cost slope only among critical activities, and re-run the forward pass after any duration change before answering questions about float or the critical path.
Mixing up BCWS, BCWP, and ACWP, or flipping the sign convention when computing cost and schedule variance, and defaulting to EAC equals budget at completion plus actual cost regardless of the performance trend.
The three earned value quantities sound alike and the formulas are memorized as strings rather than as definitions, so under exam pressure the wrong term gets substituted.
What to do instead
Write the EVM identity sheet from memory (SV, CV, SPI, CPI, EAC, ETC, VAC, TCPI), state each term in words before computing, and practice recognising from the wording which EAC variant is intended (atypical variance, typical variance, or both cost and schedule constrained).
Treating any forecast change, re-baselining request, or internal replan as an automatic adjustment to the performance measurement baseline.
Candidates conflate updating a forecast with changing the authorised baseline, so they answer that budget at completion moves whenever the estimate at completion moves.
What to do instead
Learn the three-way distinction (forecast update, internal replan within the control account, formal baseline change through change control) and answer every baseline question by asking first whether an approved scope change exists.
Classifying quality costs, direct versus indirect costs, or sunk and opportunity costs by the label on the line item instead of by the definition of the category.
Business and cost management questions use everyday words like 'inspection' or 'training' that feel like overhead, and candidates assign them by intuition rather than by the prevention, appraisal, and failure framework or by traceability to a deliverable.
What to do instead
Build a decision tree for each classification scheme (prevention, appraisal, internal failure, external failure; direct versus indirect; relevant versus sunk) and sort fifteen mixed cost items into it before checking answers.
Treating profit, cash flow, and funding requirements as interchangeable, or ignoring the time value of money when comparing payment terms and retainage.
Candidates equate money earned with money received and skip discounting because the arithmetic feels optional, so they pick the option with the highest total value rather than the highest present value.
What to do instead
Practice three or four cash flow problems that require drawing the monthly outflow and inflow curve, then discounting each option to a common date; always state the discount rate and the reference date before selecting an answer.