Smart Bidding and conversion windows: why last week is never finished

A conversion window is how long after a click a conversion can still be counted for it. It is set per conversion action, from 1 to 90 days. The default for clicks is 30 days.

Set the window to how your customers actually buy. A one-click shop rarely needs 90 days. A B2B service whose leads close in six weeks needs more than 30.

The standard Conversions column puts each conversion on the date of the click. A sale on Friday from a click two Mondays ago adds a conversion to that Monday. Every recent day will gain conversions as the window plays out.

This is why last week always looks like the worst week. It is not finished. Judge it as finished and you pause a keyword, cut a budget or lower a target on numbers that are still arriving.

1. 1

   Measure the lag

   Find how many days it takes for, say, 90% of your conversions to arrive. For a shop it may be two days. For a lead business, three weeks.

2. 2

   Leave those days out

   When you compare periods, end the window that many days before today, so both periods are complete.

3. 3

   Compare like with like

   Compare the same number of complete days, against the same days of the week.

4. 4

   Act on trends, not one week

   One bad complete week is a question. Two in a row, with the same cause, is an answer.

After a new bid strategy or a large change to target or budget, Smart Bidding shows 'Learning' while it recalibrates. Google says this typically takes one or two conversion cycles, where a cycle is the time your conversions take to arrive.

During learning, cost per conversion often swings. Making another change in that time restarts the clock. Space bid changes out, a week apart at least, so each one can be read before the next.

A target CPA or ROAS asks the bidding to reach a number. It needs enough conversions to learn what reaching it takes. Without steady conversions month after month, Maximize conversions without a target is usually the better start.

Set a first target near what the campaign achieves today, then tighten it in steps. A target far below the actual cost throttles the campaign: it holds back, buys fewer clicks and learns even less.

When the sale happens offline, in a CRM or on the phone, Smart Bidding only learns about it if you send it back. Offline conversions must be uploaded within the conversion window of their action, and no later than 90 days after the click.

Upload them often, ideally daily. A sale the bidding hears about six weeks late teaches it far less than one it hears about tomorrow.

• Data exclusions tell Smart Bidding to ignore days when tracking was broken, so it does not learn from a false drop.
• Seasonality adjustments warn it about a short, expected jump in conversion rate, such as a flash sale of a few days.

Both are under Tools, then Adjustments, in Google Ads. Use them for short events, not for ordinary weekly ups and downs.

The audit measures how long the account's conversions keep arriving after the click, and flags reports read before they are finished. Bid changes are spaced apart, and a target is never set before the campaign has enough conversions to learn from.