The Acquisition Payback Audit

I want you to help me work out what it actually costs to
acquire a customer through each of these channels: channels I have not named yet (ask me first).
The decision this needs to inform: not decided yet — ask me before continuing.

Your job is not to hand me one CAC number or tell me whether
I've cleared some external benchmark. Your job is to build the
real, fully loaded numbers and compare my channels to each other.

I will give you spend data by channel, and a CRM or billing
export I can follow forward for at least 90 days per customer.

Work through these stages, in order, as your working:

1. SET THE FRAME AND INVENTORY THE EVIDENCE
Read back the channels in scope and the decision this is for.
If I haven't told you one of these, ask. Then list what I gave
you: each file, its columns, its row count and date range, and
what the stages below need that isn't there. Say now whether I
gave you margin per customer, revenue per customer, or neither,
because stage 3 depends on it.

2. LOAD THE REAL COST
For each channel, build a fully loaded CAC. Start with direct
spend. Then take every other cost I gave you one at a time and
decide which kind it is: a cost incurred by one channel belongs
to that channel in full, and only a genuinely shared cost gets
allocated, by a rule you state and apply the same way to every
channel. Say which treatment you gave each cost line and why;
do not describe one rule as covering all of them. Also build
the company-wide blended, fully loaded CAC. Never let one
substitute for the other in anything you write.

3. FOLLOW THE CUSTOMERS FORWARD
For each channel, calculate gross margin per acquired customer
at 30, 90, 180, and 365 days. If I gave you revenue per customer
but not margin, apply the company-wide gross margin rate I gave
you and label every figure that rests on it. If I gave you
neither margin nor a rate, rank on revenue and say so in every
place the number appears. A window is partial if any customer in
the cohort has not reached it yet: report it as partial with the
count who have, rather than estimating the rest. At the same
windows, report retention per channel. Where I have told you
what makes a customer worth having here - a maintenance or
service agreement, a repeat purchase, staying active - measure
that, and put it in the ledger rather than under it. If I
haven't told you, say which you measured and why.

4. MEASURE WHAT THEY CAME BACK FOR
Skip this stage and say you skipped it if my records cannot tell
a repeat customer from a new one. Otherwise: many businesses earn
most of their margin after the first sale, through a maintenance
or service agreement attached at the point of sale, a renewal, or
a second job. For each channel report the attach rate (the share
of its customers who took one, with the numerator and denominator
shown), the repeat rate at 180 and 365 days, and the margin those
repeats added, kept separate from first-sale margin. Then rank
the channels by attach rate as well as by cost, and say where the
two orders disagree. That disagreement is usually the finding:
the cheapest channel and the one whose customers stay are often
not the same channel. Do not infer a repeat from a matching name
or address unless I have told you that is how the system records
them.

5. FLAG THE MISCALCULATIONS
Check for: free trials counted as paying customers, quick
churns or refunds counted as normal wins, organic or referral
customers blended into a paid channel's numbers, and
reactivated customers counted as new. Report each separately
from the clean numbers, with the rows involved.

6. BUILD REALIZED PAYBACK
For each channel, calculate payback from actual cohort revenue
and margin month by month, not a static ARPA-over-churn
formula. Report it in months, or "not yet reached" with the
months elapsed.

7. COMPARE, DON'T GRADE
Rank channels against each other by realized 90- and 180-day
margin, not by acquisition cost alone. Do not compare any
channel's LTV:CAC or payback against an external published
threshold as if it were a pass/fail test.

8. DECIDE, PER CHANNEL
For each channel, one of: grow it, hold it, fix the
qualification, test it before trusting it, or cut it. For
anything where the underlying conversions might not be
incremental, branded search chief among them, recommend a test
rather than a verdict, and say what evidence would settle it.
For every decision, the result that would reverse it.

HOW TO REPLY
Do the stages above as your working. Do not show me the working.
If a stage needs an answer from me, ask that one question and
stop. Otherwise reply with the headline and the brief alone, in
the shape below, and lead with the headline every time, even
when the news is that nothing needs to change.

Keep the writing under 900 words and the whole reply, table
included, under 1,200, and count both before you send it.

THREE THINGS ARE OUTSIDE THAT BUDGET AND CANNOT BE SHORTENED,
MERGED AWAY, OR DROPPED TO MAKE ROOM: the headline's four lines,
the required lines in section 1, and the rows of the table.
Write those first, then spend what is left of the budget on the
prose. If you are over, tighten sentences and cut adjectives
everywhere; if that is not enough, shorten sections 3, 6, 8 and
9, in that order. Never buy words by dropping a finding, a row,
a number, or a required line.

Inside the table, every cell is a phrase rather than a sentence,
about a dozen words at most; anything that needs a sentence to
be fair belongs in "What to change" or "Still to confirm".

BEFORE YOU SEND IT, CHECK ALL FIVE:
- the headline is four labelled lines, under 120 words, and
  names the specific thing rather than a category;
- section 1 carries every required line, with "none" written in
  where one does not apply;
- every finding you named has a size, or a stated reason it
  cannot be sized;
- every row you merged says that it is merged;
- both word counts are inside their limits.
If any of these fails, fix it and take the words from the prose.

If I say "show your working", show the ledger and every rule you
applied.

THE HEADLINE
Open with this. Four labelled lines, under 120 words in total,
before any scope, method, or description of what I sent you.
Someone who reads only these four lines has the answer.

- The finding. One or two sentences naming the specific thing
  that is holding the business back, or where the money is
  going. Name the thing, never the category: not "a process
  issue" but the step, the channel, the queue, the person's
  calendar. Where the records disagree with what I believed,
  that contrast belongs here and nowhere else.
- What it costs. The single number that sizes the finding, with
  its period and unit, and the one line of arithmetic behind it.
  If the evidence cannot put money on it, size it in the unit it
  can - hours, days waiting, deals, seats - and say plainly that
  money isn't available and why.
- Do this first. The cheapest fix, what it costs, and who does
  it. Then, if I asked you to decide something, the answer in
  one line, labelled a judgment where it is one.
- How sure. "High confidence: from your own records", "Medium:
  your records plus what you told me", or "Low: mostly what you
  told me" - then the single thing that would most change the
  answer if it turned out otherwise.

THE BRIEF
Everything below supports the headline for a reader who wants
more. Expand it; do not restate it in the same words.
1. What this ran on. Labelled lines, not prose. These are
outside the word limit and none of them may be dropped; write
"none" where one does not apply.
- Scope and period.
- The decision this is for.
- Scored: what you included, and how many.
- Excluded: how many, why, and what they were worth.
- Evidence pulled: the date the records were pulled.
- Computed with: the tool you used and the rule you applied, or
  that you had no tool and worked from summary figures.
2. What the evidence covered. Three to five bullets: what I gave
you, the period it covers, and what was missing that would have
changed the answer.
3. What we found. One paragraph, under 150 words, in plain
words: how the work actually runs and what the evidence shows,
in enough detail to make the headline's finding stand up.
4. The numbers. Blended fully loaded CAC, the range of fully
loaded CAC across channels, and realized 180-day margin per
customer for the best and worst channel, kept separate. For
each: how it was computed and which rows it rests on.
5. The ledger. One table, one row per channel: fully loaded CAC,
customers won, 90- and 180-day margin per customer (or revenue,
labelled), retention at 90 and 180 days, the attach or repeat
rate where stage 4 measured one, payback in months, the
decision, and what would reverse it.
A finding too small or too uncertain to act on still gets its own
row, marked as such. Where the table is long, you may merge rows
only when they are the same kind, and the merged row has to say
so. Never drop one.
6. What to change. Every fix, cheapest first, the headline's
included, with one line each on why the more expensive ones
aren't needed yet.
7. How you'd know it worked. For each fix, in this order and
always these four: the measure, named the same way you would
name it again next time; its baseline today, with the date the
evidence was pulled; the target; and the result that would mean
the diagnosis was wrong. Write them so someone re-running this
in a month can line their numbers up against yours without
having to interpret anything.
8. Still to confirm. Up to four things the evidence couldn't
settle, each with exactly what would settle it.
9. Not claiming. Up to five claims you are refusing to make, one
line each.

RULES THROUGHOUT
- If you have a code or data-analysis tool, use it for every
  count, median, and total, and state the rule you applied. If you
  don't, say so and ask me for summary tables instead of raw
  exports.
- Never invent a number that is not in my evidence. Where a
  value is blank, say so and leave it out of the totals rather
  than estimating it.
- Numbers I gave you in the walkthrough count as evidence: use
  them where the records have nothing, and label each one as my
  estimate.
- Never quote an industry benchmark, average, or percentage from
  outside my data, even if I mention one. If I ask how I compare
  to one, tell me plainly that you are not going to and why,
  rather than leaving the question unanswered.
- My exports often cut the same figures more than one way.
  Before adding two numbers together, check they come from the
  same cut; if they do not, report them side by side and say which
  values may be counted in both rather than summing them.
- Where I have told you something happens off-system or goes
  unlogged, silence in the records there is not evidence of
  anything. Say what would need to be logged.
- Where you nest one finding under another as its cause, the
  parent carries the rolled-up total of everything beneath it,
  labelled as a roll-up so no figure is counted twice. Every item
  you size belongs to exactly one total, and no finding you name
  is left without a size unless you say what is missing to size
  it.
- Keep observed facts, inferences, and unknowns separate. It is
  fine, and often correct, to conclude the evidence cannot settle
  something.
- If I push you for a verdict on the decision afterwards, give
  your best read, label it a judgment rather than a finding, and
  say what would change it.