Cross-Platform Measurement: Why the Numbers Never Match
Your first channel says it brought you forty sales. The second says thirty-five. And your sales for the month are fifty.
Why the Numbers Never Match
By the end of this lesson you will be able to:
- Understand that the sum of platform claims exceeds your sales, and that this is not lying
- Know the three reasons: the window, the model, and double counting
- Draw the line between measuring one channel and measuring across channels
- Know when it does not concern you — including having few enough sales to ask rather than measure
You run two advertising channels.
The first says: I brought you forty sales. The second says: I brought you thirty-five.
And your sales for the month: fifty.
The rule this course rests on
Every platform claims the same sale — and the sum of their claims exceeds your sales.
Read it twice.
And it is not lying. Each platform tells the truth from its own angle: "this person saw my advert then bought" ← and they may have seen two adverts, searched, asked a friend, then bought.
And the mistake is not in the platforms ← but in adding their numbers together.
Three reasons the numbers never match
1. The window ← each platform credits itself with what happened within a certain period after the interaction ← and the periods differ (lesson four).
2. The model ← who gets the credit when more than one source is involved: the first, the last, or all of them? ← and each platform answers in its own favour (lesson five).
3. Double counting ← the same event sent twice and counted twice ← and this is a technical error that gets fixed (lesson three).
And all three together mean: the numbers can never match ← and the goal is not for them to match, but to know by how much they differ and why.
Four questions this course answers
1. What exactly do I count? ← (lesson two).
2. Why is my number on the platform different from my number in my store? ← (lessons three and four).
3. Which channel actually deserves the credit? ← (lesson five).
4. What do I do about what no platform sees? ← (lessons six and seven).
And try them now: add up what your channels claim this month, and compare it against your sales ← and the difference is why you are here.
What this course is not
It is not about measuring one channel — that is in "Running Google Ads Yourself", lesson six, which covers defining a conversion and the four ways figures deceive you inside a single channel. This is about the contradiction between two channels or more.
Nor is it about your own data — your questions, your inventory and your comparisons are in "Analysing Your Business Data", and we will use its rules in lesson seven.
Nor is it about ownership and permissions — that is the "Business and Ad Accounts" course, and the measurement tool is an owned asset like any other.
And I will not explain the interface buttons or name a tool. Tools change their names and screens every few months ← and what does not change is that all measurement rests on four things: what you count, how the event arrives, which window it is credited to, and which model distributes the credit.
And I will not mention a single figure of my own — nor a "usual" gap rate ← these differ by field, channel and market, and a published figure becomes a reference the reader measures themselves against on no basis.
When this course does not concern you
Three cases, and I will say them before you continue:
1. You have only one channel ← so there is no contradiction to resolve ← read lesson six of "Running Google Ads Yourself" and it is enough.
2. Your sales are few enough that you know where each one came from ← so ask rather than measure ← and asking is more accurate than any tool at small counts.
3. You do not spend on more than one channel ← and do not intend to ← so this course solves a problem you do not have.
And the second is the one people resist: measurement is a tool for large counts — and at small ones, the direct question is more honest and cheaper.
What you need to start
- At least two advertising channels — or a channel and a free source
- Your actual sales figure for each month ← from your store or your book
- One definition of what you count as a conversion — and you will write it in lesson two
- Half an hour a month
Action steps
- Write the rule: the sum of platform claims exceeds your sales.
- Add up what your channels claim this month and write the total.
- Write your actual sales beside it.
- Compute the difference — and do not fix it yet.
- Stop adding platform numbers together in any report.
- Go honestly through "when this does not concern you", starting with the second.
- Do not compare yourself against any published rate.
- Write the four questions and record where you hesitated.
That was the full sample — here is the rest
What you just read is one part. The full edition includes:
- All 8 lessons: why they never match, what you count, how the event arrives, the window, the model, what platforms do not see, and the truth panel
- The hands-on task and quiz that close every lesson — neither is included in this sample
- A capstone leaving you with four documents and a one-page monthly panel, a 32-question audit and a ninety-day plan
- A completion certificate in your name, in Arabic and English