Key takeaways
- Define the earnings measure before changing assumptions.
- Separate the time effect from additional expenses.
- Use a labelled cost assumption for the specific delay being tested.
- Calculate the threshold that would change the decision, not just a percentage decline.
- Treat sensitivity as a conditional calculation rather than a forecast or claim assessment.
Choose one question the test can answer
A sensitivity test asks what happens if a specified input changes while the stated remaining assumptions hold. It is useful for identifying which uncertainty deserves attention and where a recommendation might reverse.
For a delay test, state what the extra time represents. A longer sea passage, a waiting period and an extended service operation may affect different expenses. Do not apply a single daily cost to every type of delay without a supported basis.
The fictional model here deliberately uses a fixed additional cost per delay day so the arithmetic can be inspected. A real voyage model should use the actual relevant cost behaviour and distinguish fixed, variable and conditional items.
Also state whether revenue changes. If a potential recovery or extra payment depends on the actual terms, keep its assessment separate. The sensitivity calculation does not establish entitlement or collection.
Define contribution and duration consistently
For this article, illustrative voyage contribution means a defined revenue amount less the listed voyage costs. Daily contribution is that amount divided by the model's total days. It is not net profit or a universal definition of a published earnings measure.
Keep the same start and endpoint throughout the test. If an alternative delay scenario changes the ending position or requires another movement, the comparison needs that additional scope. A longer duration is not necessarily the only consequence.
The base contribution should already include the costs belonging to the base voyage. Add only the incremental expenses caused by the tested change. Otherwise the sensitivity may count an existing cost a second time.
This separation lets the desk explain the result. A decline caused mostly by the time denominator calls attention to the use of vessel time; a decline driven by a large extra service cost points to a different commercial question.
Illustrative delay sensitivity
ILLUSTRATIVE fictional model. Base voyage contribution is USD 900,000 over 30 days, producing USD 30,000 per day. Every additional delay day is assumed to add USD 10,000 of listed costs, with revenue unchanged. These figures are invented and are not operating benchmarks.
For an additional delay of d days, contribution equals USD 900,000 minus USD 10,000 multiplied by d. Duration equals 30 plus d. Daily contribution equals the resulting contribution divided by the resulting duration.
| Additional delay | Contribution | Total days | Daily contribution |
|---|---|---|---|
| None | USD 900,000 | 30 | USD 30,000.00 |
| 1 day | USD 890,000 | 31 | USD 28,709.68 |
| 3 days | USD 870,000 | 33 | USD 26,363.64 |
| 5 days | USD 850,000 | 35 | USD 24,285.71 |
At five additional days, daily contribution falls by USD 5,714.29 from the base result, a reduction of about 19.05%. The decline is not calculated by deducting USD 10,000 from the daily earnings figure. That USD 10,000 is an incremental cost per added day, while the total contribution is spread over a longer voyage.
The distinction prevents a common dimensional error. A cost per extra day enters the numerator through the number of extra days. The final daily earnings measure divides the entire revised contribution by the entire revised duration.
Separate the denominator effect
ILLUSTRATIVE decomposition of the five-day case. If contribution stayed at USD 900,000 but duration increased to 35 days, daily contribution would be USD 25,714.29. The time-only reduction from the base is USD 4,285.71 per day.
The assumed USD 50,000 of incremental costs then reduces the 35-day result by another USD 1,428.57 per day, reaching USD 24,285.71. The two components sum to the USD 5,714.29 decline, subject to displayed rounding.
This decomposition explains the arithmetic rather than allocating responsibility. It does not imply that time has a separate invoice value equal to the calculated reduction. The model's daily result is an analytical measure, not a claim amount.
It also does not make the time-only scenario an operationally realistic alternative. Some delays necessarily bring additional costs. Holding contribution fixed is a mathematical comparison used to show how the denominator works.
Find the decision threshold
A sensitivity table becomes more useful when connected to a decision condition. The business may have an explicitly chosen minimum daily contribution for this comparison. State that threshold and its purpose rather than implying it is an industry standard.
ILLUSTRATIVE threshold. Assume the fictional decision requires at least USD 25,000 daily contribution under this model. Solve:
(900,000 − 10,000 × d) ÷ (30 + d) = 25,000.
Rearranging gives 150,000 = 35,000 × d, so the threshold is approximately 4.286 additional days. At four additional days, contribution is USD 860,000 over 34 days, or USD 25,294.12 per day. At five additional days, the result is below the fictional threshold.
This is a decision boundary within the assumptions. It is not permission to incur that delay, a prediction of its likelihood or a substitute for operational feasibility. If revenue, cost behaviour or the comparison horizon changes, recalculate the boundary.
Use the result to prioritise evidence
The test shows which input matters to the recommendation. If the feasible delay range sits comfortably on one side of the threshold, more precision may not change the choice. If the range straddles the threshold, better evidence about timing or incremental costs can be particularly valuable.
Ask the responsible parties for information that narrows the relevant uncertainty. A general market update may be less useful than confirmation of the specific service window on which the duration depends.
Do not mistake a single-input test for a complete downside analysis. Other variables may move with delay, including service scope or revenue conditions. Where those connections matter, construct a coherent scenario with the linked changes instead of relying on the isolated sensitivity alone.
Keep the recommendation conditional on the evidence. A clear statement such as the result meets the stated threshold only within the supported duration range is more informative than calling the voyage robust without explaining why.
Common mistakes
One error is subtracting a delay-day cost directly from an already calculated daily earnings figure. Another is increasing the duration while forgetting the additional expenses explicitly assumed by the scenario.
A third mistake is treating the threshold as a forecast or an operational allowance. Finally, do not convert a modelled earnings reduction into a contractual claim without a separate assessment of the actual terms and evidence.
Where Zeaclub fits
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Educational information only; not legal, financial or trading advice. Contract wording and applicable rules control. Verify current requirements and obtain qualified advice before acting.
Frequently asked questions
Why does delay affect the daily result twice?
In this model, it adds costs and increases the time over which contribution is measured. Actual cost behaviour must be assessed for the specific event rather than assumed from the example.
Is the decline linear as delay increases?
The numerator changes linearly under the fictional cost assumption, but dividing by an increasing duration produces a non-linear daily result. Recalculate the ratio for each case.
Does the threshold predict an acceptable delay?
No. It identifies where this calculation crosses an explicitly chosen economic condition. Operational acceptability and contractual consequences are separate questions.
Should possible extra revenue be included?
Include it only on an appropriately supported or clearly labelled conditional basis. Do not treat an uncertain recovery as established revenue merely to preserve the base earnings result.
What should follow a sensitivity test?
Investigate the inputs that could change the decision, assess connected scenarios where needed, and update the comparison when material evidence changes. The test should guide useful work rather than produce an isolated table.