The IIBA BABOK Guide v3 structure of business analysis work across six knowledge areas, each with its own tasks, inputs and outputs — the backbone of the ECBA, CCBA and CBAP exams.

When to use: As the organising structure for any BA engagement, and as the primary study map for IIBA certification exams.

MoSCoW Prioritisation

A requirement prioritisation technique classifying scope into Must have, Should have, Could have and Won't have this time, used to protect a timeboxed delivery.

When to use: When scope exceeds a fixed time or budget and stakeholders must make explicit trade-offs — especially in agile and DSDM delivery.

Use Case Modeling

A behavioural technique describing how actors interact with a system to achieve a goal, captured as a use case diagram plus structured textual specifications.

When to use: When functional requirements involve significant interaction and flow variation, and to give developers and testers a shared, testable narrative.

Formulas library

Every formula with variables, interpretation thresholds and a worked example.

Expected Monetary Value

EMV = Probability x Impact

P: Probability of the event (%)
I: Monetary impact if it occurs (USD)

> 0 — Net opportunity
= 0 — Neutral
< 0 — Net threat

Worked example

A vendor integration has a 30% chance of a late delivery that would cost $80,000 in rework and penalties.

EMV = 0.30 x -80,000 = -24,000

Reserve $24,000 of contingency for this single risk, or spend less than that to mitigate it.

Try: A vendor integration has a 30% chance of a late delivery that would cost $80,000 in rework and penalties.

Three-Point (Beta) Estimate for requirements effort

E = (O + 4M + P) / 6

O: Optimistic effort (hours)
M: Most likely effort (hours)
P: Pessimistic effort (hours)

> 0 — Weighted estimate

Worked example

Eliciting and documenting requirements for a payments module: optimistic 60 hours, most likely 90 hours, pessimistic 150 hours.

E = (60 + 4x90 + 150) / 6 = 95

Commit to 95 hours and communicate a 80-110 hour one-sigma range to the sponsor.

Try: Eliciting and documenting requirements for a payments module: optimistic 60 hours, most likely 90 hours, pessimistic 150 hours.

Cost-Benefit Ratio

BCR = Total benefits / Total costs

B: Total discounted benefits (USD)
C: Total discounted costs (USD)

> 1.5 — Strong business case
1 - 1.5 — Marginal business case
< 1 — Not justified

Worked example

A self-service portal is forecast to deliver $1,800,000 of discounted benefits against $1,000,000 of discounted costs.

BCR = 1,800,000 / 1,000,000 = 1.8

Every dollar spent returns $1.80 of benefit — a strong case that survives moderate estimate error.

Try: A self-service portal is forecast to deliver $1,800,000 of discounted benefits against $1,000,000 of discounted costs.

Weighted Scoring Model (3 criteria)

Score = SUM(weight x rating) / SUM(weight)

w1..w3: Weight of each criterion (weight)
s1..s3: Rating of the option against each criterion (1-10)

> 7.5 — Strong fit
5 - 7.5 — Acceptable fit
< 5 — Weak fit

Worked example

Selecting a CRM. Criteria: functional fit (weight 5, rated 8), total cost (weight 3, rated 6), integration effort (weight 2, rated 4).

Score = (5x8 + 3x6 + 2x4) / (5 + 3 + 2) = 66 / 10

An acceptable but not standout option — the low integration rating is what pulls it down.

Try: Selecting a CRM.