Measuring what works

Last click attribution: the default model, and who it flatters

Last click attribution gives all the credit for a sale to the final marketing touch before the order.

About the Google Ads connector

If a customer saw three ads and read two emails, then clicked a paid search result and bought, paid search gets the whole sale and the rest get nothing.

Why it matters

It is the default in many reporting tools, so if you have never chosen a model, this is the one your numbers are built on. The decision it changes is which channels look cheap and which look expensive, and so which ones get more budget. Under last click, the channels that close sales look cheap and the channels that start them look like they do nothing.

How it works

The rule is to find the last touch before the order and credit it with the order. There is no weighting to argue over, and the result tends to match what the platforms themselves report, which is why it survives.

Here is an illustration with made-up numbers. A shop takes 100 orders in a month from four channels.

The last click column adds up to 100 because every order has exactly one last touch. The final column does not add up, because one order can have several channels on its path; it is there to show how often each channel was present at all.

Read the cost per order column as a last click report would. Brand search costs £10.00 an order and prospecting costs £100.00. The obvious move is to cut prospecting and put the money into brand search. The final column tells a different story. Prospecting was on the path of 55 orders and brand search on 70, and most of the people searching your brand name had heard of it somewhere. Cut prospecting and, a month or two later, the brand searches start to dry up, and the £10.00 cost per order with them.

What it can't tell you

It flatters brand search, because people who already know you search for you last, and retargeting, because it reaches people who have already visited and are close to buying. Both sit at the end of the path by their nature. Last click reads that position as merit.

It starves anything upper-funnel. Prospecting ads and the first email in a sequence introduce people who then convert through something else. Under last click they show a cost and no return, and they are the first thing cut when the budget tightens.

It also can't see cause. A brand search click credited with a sale may have been a customer who would have typed your web address. The attribution models page shows how the other rules split the same path, and the incrementality testing page covers the only way to find out whether a touch changed anything.

When to use it

Use it as your baseline. Everyone understands it and it reconciles to the platforms, so it needs no explanation in a meeting. Using it alone, and believing the cost per order column, is the mistake.

Pair it with a first click view of the same month. The two together show you the opener and the closer for each channel. If a channel looks worthless under last click but shows up on half your paths, test it with a holdout before you cut it.

Tracking it in a spreadsheet

The inputs are orders and spend under last click. A scheduled Fresh Sheets report can keep Google Ads cost and conversions current in a tab of their own, each conversion action counted under the model you chose for it. Fresh Sheets replaces that tab's contents on every refresh, so keep the cost per order arithmetic, and the first click comparison, on a separate tab.