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Methodology

Customer Retention Profit Impact Planner methodology

Compare a proposed retention scenario with the current cohort and test whether its incremental contribution covers programme cost.
Duc Nguyen X.By Duc Nguyen X.· Founder, Margin101Last reviewed: View update historyMethodology

Educational only: Business decision support, not accounting, tax or legal advice.

Privacy: Calculations run locally; Margin101 does not receive your commercial inputs.

Update policy: Reviewed when formulas or official dependencies change.

Scope: Market-neutral small-business planning using your own assumptions.

1. Formulas and units

Additional Retained Customers
additionalRetainedCustomers = customers × (proposed retention rate − baseline retention rate)

Where

customers
Customers in cohort (whole or operational units)Source: Business record
baselineRetentionRate
Baseline retention rate (decimal rate)Source: Business record
proposedRetentionRate
Proposed retention rate (decimal rate)Source: Business record
additionalRetainedCustomers
Additional Retained Customers (units)Source: Calculated output
Incremental Contribution
incrementalContribution = additional retained customers × contribution per retained customer − programme cost

Where

customers
Customers in cohort (whole or operational units)Source: Business record
contributionPerRetainedCustomer
Contribution per retained customer (currency units on one consistent basis)Source: Business record
programmeCost
Retention programme cost (currency units on one consistent basis)Source: Business record
additionalRetainedCustomers
Additional Retained Customers (units)Source: Calculated output
incrementalContribution
Incremental Contribution (money)Source: Calculated output

Money inputs and outputs use the currency selected in the scenario without changing the canonical methodology. Rates, margins, utilisation and buffers are entered as percentages and converted to decimal values for calculation.

2. Worked example

Input assumptions

Worked values below come from the same registered engine and visible default assumptions.

Calculation and outputs

Example

Worked values below come from the same registered engine and visible default assumptions.

Additional Retained Customers
10
Incremental Contribution
1,500.00 currency units

The exact engine-derived outputs are shown in the labelled rows below.

Interpretation

Use the result to compare baseline and proposed retention assumptions for one cohort and period, not as a retention forecast.

3. Validation and boundary checks

  • Customers must be a finite, non-negative whole cohort count; both retention rates must remain between 0% and 100%.
  • Contribution per retained customer and programme cost must be finite and non-negative.
  • A proposed retention rate below baseline is valid and produces a negative retained-customer change rather than an input error.
  • Incremental contribution must reconcile to additional retained customers × contribution per retained customer − programme cost.

4. Assumptions and source classification

  • Baseline and proposed retention rates are user-entered scenarios for the same cohort and period, not forecasts or causal estimates.
  • Contribution per retained customer and programme cost use the same period and currency basis, with both entered excluding indirect tax.
  • No provider rate, market benchmark, country rule or policy constant is embedded.

This planner has no current policy-data dependency. Its commercial assumptions are user supplied. Registered family-level regression suites exercise the shared business-logic engine and worked-result reconciliation.

5. Limitations

  • The workflow compares two retention assumptions; it does not predict whether a programme will cause the proposed rate.
  • It excludes acquisition, serving-capacity and secondary behavioural effects unless they are already reflected in the user-entered contribution and programme cost.
  • It does not replace financial, accounting, tax or legal advice.

This is educational decision support, not tax, accounting, legal or financial advice. Check the treatment of your actual transactions under the rules that apply to your business and seek qualified advice where appropriate.

6. Update and evidence policy

Registered family-level suites test formula invariants and example reconciliation; the release ledger records that coverage without claiming a separate oracle for every line of public copy. There is no official threshold or benchmark to refresh for this planner. Commercial inputs remain user-supplied because they vary by business and contract.

Change history

  1. : Initial public release of the planner and methodology after pre-launch calculation, content, source and interaction review.

Related reading

Guides to interpret the decision and its assumptions.

  • Loyalty Program Economics

    Compare incremental retention contribution with reward and programme costs over a finite cohort horizon.

    Read guide

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