WEBVTT

NOTE IDER in-house training materials. Captions follow measured phrase audio timings.
Hypothetical worked cases; figures are instructional examples.

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Imagine a service business comparing two urban
locations. One has stronger apparent demand; the other

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offers easier access and lower operating costs. The
practical question is not which location looks

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busiest.

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It is which location can support the intended service,
at an acceptable risk, under an explicit set of

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priorities. In this IDER in-house clinic, we will
build that decision from observable evidence.

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All locations and figures are hypothetical teaching
examples. Keep a spreadsheet nearby.

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You will calculate a ranking, discover when that
ranking reverses, and test whether the preferred

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option actually covers its operating costs.

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The final product is a recommendation another analyst
can reproduce and a manager can challenge.

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Start with conditions that a location must satisfy
before you compare its attractiveness.

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If the service requires reliable power and a site
cannot supply it at a feasible cost, an attractive

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demand score should not compensate for that failure.

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Write each gate as a test, with an evidence source and
an accountable reviewer. Then identify genuine

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trade-offs among eligible sites.

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A slightly longer journey may be acceptable if
customers obtain better service or lower prices. This

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separation prevents an impressive weighted average
from hiding a fatal constraint. Record exceptions

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explicitly.

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An unresolved permission issue belongs in a
conditional decision, not inside a quietly reduced

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score that executives might never notice.

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A circular radius on a map is convenient, but it
rarely describes the journey customers actually make.

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Build catchments using the transport modes and hours
relevant to your service.

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A road crossing, transfer or flooded route can change
effective access without changing physical distance.

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Sample customer origins and ask which alternative
destination they would use. This reveals overlapping

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catchments and substitution.

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Also define your unit carefully. The same commuter
passing twice is two observed visits, not necessarily

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two people or two purchase opportunities.

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For a practical study, maintain separate fields for
eligible visits, identifiable customers and completed

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purchases. That distinction will become essential when
we turn observed movement into a contribution

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forecast.

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Suppose your team counts Site A on a payday evening
and Site B on a quiet weekday morning. Precise

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counting will not repair that comparison.

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Create a schedule crossing the time periods and day
types that matter, then observe both sites within

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comparable strata.

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Expand each stratum using the number of similar
operating periods it represents, rather than

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multiplying one convenient hour across the month.

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Record unusual weather, promotions and closures so
that analysts can investigate anomalies. Repeated

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observations within one day may share the same shock,
so do not treat every minute as independent evidence.

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Before leaving the field, reconcile observer
definitions using a short joint counting exercise and

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review disagreements.

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Our illustration assigns each site a score for demand,
access and cost attractiveness. Higher always means

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better, including for cost, where a cheaper comparable
operating arrangement receives a higher score.

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The numbers are useful only after you define their
anchors. For example, specify what zero and one

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hundred mean and why intermediate performance deserves
its position.

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Otherwise two assessors may attach different meanings
to eighty. Avoid scoring the same benefit twice

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through correlated criteria such as footfall and
forecast sales unless the model explicitly separates

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their contributions.

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Keep the raw measurements alongside the converted
scores. When someone disputes the ranking, you can

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then distinguish a disagreement about observed
performance from a disagreement about priorities.

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We now apply demand, access and cost weights of fifty,
thirty and twenty percent. Site A receives forty

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points from demand, eighteen from access and eight
from cost, giving sixty-six.

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Site B receives thirty-two point five, twenty-five
point five and fifteen, giving seventy-three. These

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are preference scores, not probabilities of commercial
success.

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Elicit weights against the defined improvement from
the worst to the best performance on each scale.

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Asking which criterion sounds most important without
showing that range can create misleading weights.

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Record whose preferences the weights represent and
obtain their confirmation before revealing the final

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ranking. This reduces the temptation to adjust the
model until it endorses a favourite site.

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Pause the video and challenge the baseline. A decision
maker now proposes a seventy percent demand weight,

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while keeping the relationship between access and cost
weights at three to two.

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First calculate the new access and cost weights. Then
recompute both site scores without changing their

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underlying performance.

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Finally, write one sentence explaining whether a
changed ranking would indicate better evidence or

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different preferences.

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That final distinction matters in practice: a model
can change its recommendation even when no new

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observation has been collected. Show your intermediate
contributions rather than only the totals.

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If your weights do not add to one hundred percent,
correct the model before interpreting any resulting

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ranking.

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The remaining thirty percent divides into eighteen
percent for access and twelve percent for cost. Site A

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now scores seventy-one point six, while Site B scores
sixty-nine point eight.

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The ranking reverses because Site A's demand advantage
receives more influence. Nothing in this calculation

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proves that the original observations were wrong. You
have changed the decision maker's valuation of

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performance differences.

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In a committee discussion, show both scenarios and ask
whether the higher demand priority reflects the actual

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business strategy. Also check whether all participants
understood the same performance ranges.

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A useful sensitivity analysis reveals a consequential
disagreement; it does not average that disagreement

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away and present an artificial consensus as objective
measurement.

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Instead of trying isolated weights, solve for the
exact point where the two scores are equal. Let the

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demand weight be w.

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Access receives three fifths of the remainder and cost
two fifths. Site A's score becomes fifty-two plus

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twenty-eight times w. Site B's becomes eighty-one
minus sixteen times w.

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Equating them gives forty-four times w equal to
twenty-nine, so the switching point is approximately

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sixty-five point nine one percent. Below that value, B
ranks higher; above it, A does.

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This threshold is useful because decision makers can
assess a meaningful proposition: do we really value

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the defined demand improvement enough to allocate
roughly two thirds of the total weight to it?

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Weight sensitivity addresses preferences; it does not
capture uncertainty in measured demand. Treat those as

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separate layers.

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Revisit footfall estimates, conversion assumptions and
operating costs using defensible ranges linked to

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actual evidence quality. Then examine combinations
that can occur together.

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A road disruption may reduce visits and raise delivery
costs simultaneously, so independent one-variable

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changes could understate risk. Conversely, combining
every imaginable worst case without a coherent

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mechanism can exaggerate it.

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For repeated field observations, consider resampling
at the day or other relevant cluster level rather than

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individual counts.

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Report how often rankings change under the stated
scenarios, but do not call that a probability of

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success unless you have justified a probability model.

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Now move from relative attractiveness to absolute
viability. Assume twelve hundred eligible visits per

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day, a four percent purchase conversion and twenty-six
operating days. That gives twelve hundred and

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forty-eight monthly purchases.

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At thirty-five Ghana cedis contribution per purchase,
monthly contribution is forty-three thousand six

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hundred and eighty. Subtract fixed operating costs of
forty-two thousand and the surplus is only sixteen

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hundred and eighty.

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Contribution means selling price less the costs that
vary with the purchase; it is not sales revenue. This

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small surplus should immediately focus your evidence
collection on conversion and visit quality.

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It also excludes investment recovery, financing and
tax, so a positive result alone does not establish an

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acceptable investment return.

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A pilot is most valuable when it resolves a
decision-sensitive uncertainty. If the economic case

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depends on four percent conversion, simply collecting
more general footfall data may add little.

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Test the actual offer, opening hours and customer
journey at a comparable location or through a

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permitted temporary operation. Record the eligible
denominator before observing purchases and track

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repeat customers separately.

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Specify the duration and decision rule before seeing
results, including what would trigger redesign or

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further evidence.

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A short successful trial can still overstate normal
performance if novelty, discounts or exceptional

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staffing drove the outcome.

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Explain how the full operation would differ and adjust
the forecast using documented mechanisms, not a

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convenient unexplained haircut.

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Pause and calculate a combined downside. Daily
eligible visits fall by ten percent, and conversion

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falls to three point five percent. The operating
calendar, contribution per purchase and fixed costs

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stay unchanged.

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Calculate monthly contribution and the resulting
surplus or deficit. Then explain why subtracting ten

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percent from the original operating surplus would give
the wrong answer.

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The revenue-generating activity changes before fixed
costs are deducted, and conversion has changed as

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well. In your written recommendation, distinguish a
ranking conclusion from a viability conclusion.

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A site can remain the best of the compared locations
while all available options fail the business's

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minimum economic requirement. Deciding to defer is a
legitimate output of professional research.

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Ten percent fewer visits gives one thousand and eighty
per day. Multiplying by three point five percent

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conversion, twenty-six days and thirty-five cedis
contribution yields thirty-four thousand three hundred

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and ninety-eight.

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After fixed costs, the site loses seven thousand six
hundred and two cedis monthly in this scenario. Fixed

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commitments explain why the operating result
deteriorates much faster than the visit count.

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You should now investigate whether rent terms,
staffing patterns or the service offer can change

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without undermining demand. Recalculate the whole
mechanism after any proposed adjustment.

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A lower price may improve conversion while reducing
contribution per sale; treating that change as a pure

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demand benefit would repeat the same forecasting
error.

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Your decision memo should let a reviewer reconstruct
the recommendation without rebuilding the entire

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study. Show which sites passed the eligibility gates,
how the catchments were defined and when observations

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were collected.

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Present raw measures alongside scores, identify the
agreed weights and display the switching threshold.

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Then attach the operating model with baseline and
coherent downside cases.

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State a conditional recommendation in operational
language: proceed only if a specified uncertainty is

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resolved, an acceptable lease condition is obtained,
or a pilot meets the predefined requirement.

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Assign an owner and deadline to every condition.
Preserve the data version and calculation file so that

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the next update changes the evidence transparently
instead of silently rewriting the original decision.

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Before using this method in your next assignment,
audit one denominator and one scoring anchor.

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Ask whether your visits represent genuine purchase
opportunities and whether a ten-point score

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improvement means the same thing to every decision
maker. Then calculate both a ranking threshold and an

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economic threshold.

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The first tells you which option is preferred under
stated values; the second tells you whether an option

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is worth operating at all. Those are complementary
decisions.

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Complete the assessment below, then prepare the two
applied tasks using either the hypothetical case or a

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suitably anonymised project.

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Evaluate your work by traceability, coherent
assumptions and the clarity of the conditions attached

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to your recommendation, not by how confidently you
name a winner.

