CIMA P1 common mistakes
CIMA P1 · Understand the traps and how to avoid them.
Treating a stepped fixed cost as a single constant when answering a 'what if volume changes' question, then quoting one fixed cost figure across all output levels.
Candidates learn 'fixed costs do not change with output' as a rule and stop there, missing that the syllabus distinguishes committed, discretionary and stepped costs; the step point is often buried in the scenario text rather than given as a table.
What to do instead
Before calculating, scan the scenario for wording such as 'an extra supervisor is required for every 5,000 units' and build a small table of total fixed cost at each activity level in the range tested. State the relevant range explicitly in your answer, and check whether the step is crossed at the volume in the question.
Producing a full absorption costing statement when the question asks for a marginal (variable) costing figure, or mixing the two by including a share of fixed overhead in a contribution calculation.
Under exam pressure candidates default to the format they practised most recently, and the two formats share the same top lines so the error is invisible until the final profit figure is wrong.
What to do instead
Write the word CONTRIBUTION at the top of your workings whenever the question mentions marginal costing, decision making or 'variable cost'. Under marginal costing, fixed costs appear only once, below contribution, as a period cost; no fixed overhead is ever attached to units of product.
Calculating overhead absorption rates using budgeted overheads divided by actual labour hours, or using actual overheads divided by budgeted hours, instead of matching the same basis on both sides.
Candidates memorise 'OAR = overhead / base' without internalising that over- and under-absorption only exists because a predetermined rate uses budgeted figures on both sides; mixing actual and budgeted destroys the meaning of the variance.
What to do instead
Always compute the predetermined rate as budgeted overhead divided by budgeted activity, then apply it to actual activity to get absorbed overhead. Compare absorbed with actual overhead to get over/under absorption, and label each figure 'budgeted' or 'actual' in your workings.
Building a cash budget by starting from profit and adjusting, rather than from cash receipts and cash payments, so depreciation and accruals leak into the cash figures.
Profit and cash feel interchangeable to candidates who have not internalised the accruals concept, and the standard proforma is often memorised as a layout rather than as a logic.
What to do instead
Start the cash budget from receipts: opening cash, cash from credit customers using the collection pattern given, then payments for materials, labour, overheads, capital expenditure and tax. Add back depreciation only if you are reconciling profit to cash, never inside the cash budget itself.
Forecasting sales receipts without applying the collection timing pattern, so month-one sales are treated as month-one cash.
Candidates read the sales line and copy it into the cash budget because the collection percentages appear in a separate sentence and require a two- or three-month lag to be applied.
What to do instead
Before writing any numbers, draw a timeline: sales in month 1 are collected as x% in month 2, y% in month 3, with the remainder irrecoverable or in month 4. Then populate each month's receipts from the sales of earlier months, and separately list opening receivables that will be collected in month 1.
Producing flexible and fixed budget variances in the wrong direction or against the wrong benchmark, for example comparing actual cost with the original static budget when a flexed budget is required.
The three-way comparison (static, flexed, actual) is conceptually simple but easy to collapse under time pressure, and candidates forget that the flexed budget must be recast at the actual activity level before any variance is meaningful.
What to do instead
Write three columns: original budget, flexed budget at actual units, actual. Compute the sales volume variance between columns one and two, and the expenditure/efficiency variances between columns two and three. Never compare actual with the static budget for a cost variance.
Accepting a special order because its selling price exceeds variable cost, without checking whether spare capacity exists or whether the order displaces existing profitable sales.
Candidates apply the 'any positive contribution is good' rule mechanically; the rule only holds when there is genuinely idle capacity and no better alternative use of it.
What to do instead
Ask three questions in order: is there spare capacity, will accepting the order lose existing contribution, and are there incremental fixed costs such as extra tooling or a one-off delivery? Only accept if incremental revenue exceeds incremental costs including opportunity cost.
In a make-or-buy or limiting-factor question, ranking products by contribution per unit rather than contribution per unit of the scarce resource.
Unit contribution is the most familiar metric and looks like the right ranking; candidates forget that when a resource is scarce, the objective is to maximise contribution per scarce unit, not per product.
What to do instead
Identify the limiting factor first and state it. Then compute contribution per unit of that factor (per machine hour, per kg, per labour hour) and rank on that basis. Where a minimum contract quantity must be supplied, allocate the scarce resource to that obligation first, then rank the remainder.
Giving a single-point NPV or expected-value answer in a question that supplies probabilities or ranges, and ignoring the spread of outcomes entirely.
Candidates see a number to calculate and stop once they have one, treating risk as a separate topic rather than as an attribute of the decision being evaluated.
What to do instead
Where probabilities are given, compute the expected value and also state the range and the probability of a loss. Where a range is given, calculate best and worst case. Then comment on whether the decision-maker's attitude to risk would change the recommendation, since expected value assumes risk neutrality.
Confusing risk with uncertainty, and describing a sensitivity analysis as if it measured probability.
The two terms are used loosely in everyday speech, and candidates write 'the project is risky' where the question wants the specific distinction: risk has known probabilities, uncertainty does not.
What to do instead
Use the definitions precisely: risk is where possible outcomes and their probabilities are known or estimable; uncertainty is where they are not. Sensitivity analysis asks 'by how much can one variable change before the decision reverses' and says nothing about likelihood, so pair it with probability data if the question provides any.