Attribution Windows Are a Commercial Term, Not a Technical Setting

A partner asks you to move the click window from 7 days to 30. It arrives as a small technical request, usually late in an email, usually phrased as a fix. Our conversions aren’t being credited properly. Can you extend the window?

Nothing about that sentence is technical. What has just been requested is a price increase, and the increase is invisible because it doesn’t appear in the rate. The commission stays at whatever it was. The volume of sales stays exactly what it was. What changes is how many of those sales get labelled as somebody’s work, and every sale that changes label moves money.

I have agreed to window extensions I shouldn’t have, because the request was framed as a measurement correction and I answered it as one. The pattern is consistent enough to be a rule now: treat the window as a term in the contract, priced and traded like any other. Not as a dropdown.

What an attribution window actually decides

An attribution window does not decide what happened. It decides who gets paid for what happened.

This distinction sounds pedantic and it is the whole post. A customer clicked a partner’s link on Tuesday, saw two of your ads on Wednesday, searched your brand name on Friday, and bought on Saturday. That sequence is a fact. It doesn’t change when you change a setting. What changes is which of those four touches your system holds responsible on payout day.

So when someone tells you a longer window is “more accurate”, ask accurate about what. A 30-day window is more generous to the earliest touch. A 1-day window is more generous to the last. Neither is measuring the customer’s intention, because nobody can. Both are allocation rules, and an allocation rule is a commercial policy wearing a technical costume.

The second thing the window decides is subtler and it costs more. In every channel where an algorithm optimises against your conversion feed, the window defines what the algorithm is chasing. Google’s documentation is direct about it: Smart Bidding will “count and optimize conversions for any window you choose”. Widen the window and you have not just changed a report. You have changed what the bidding system believes a good click looks like, and it will go and buy more of that.

Who gains when the window gets longer, and who pays for it

A longer window transfers credit from partners who close to partners who introduce, and the bill lands on whoever holds the margin.

That transfer is not evenly distributed. It reliably favours some partner types and reliably harms others, and knowing which is which is most of the negotiation.

Read the last row again, because it is the one nobody puts on a slide. The party that pays for a wider window is frequently not another partner. It is your own unattributed and owned demand — the traffic you were going to get anyway, which now arrives with an invoice attached.

That is the whole reason a window extension can raise your blended cost of sale without raising a single rate, and without a single additional order. If you have never sat down and worked out what an order actually has to leave behind, the sheet that tells you whether your marketing makes money is the arithmetic this decision sits on top of.

Three numbers that tell you what a longer window costs, before you agree to it

You can price a window extension before agreeing to it, using data you already hold. Three numbers, in this order.

1. Your time-to-conversion distribution. Not the average. The distribution. What share of conversions land within 1 day, 7 days, 14, 30. Every major platform will show you this, and most affiliate networks will too if you ask the account manager for a lag report. If 85% of conversions already land inside 48 hours, a 30-day window is buying you almost nothing in truth and a lot in liability, because the extra 28 days are mostly catching coincidence. If the distribution has a genuine long tail — considered purchases, high ticket, B2B — the partner asking has a real case.

2. The overlap rate. Of the conversions that a longer window would newly credit to this partner, how many are already being credited to someone else, including to your own channels? This is the number that turns the conversation from generous to specific. A longer window rarely finds new sales. It mostly relabels existing ones. Both Google Ads and Meta let you model this without touching your live configuration — Meta’s Compare Attribution Settings sits in the Columns dropdown in Ads Manager and shows how conversions redistribute across windows on data you have already collected. Use it before the call, not after.

3. The new-customer share. Of the sales this partner is credited with, what fraction are first-time buyers? A partner whose credited volume is mostly repeat purchasers is being paid to stand near your existing customers. A longer window makes that worse, because repeat buyers were already coming back. This single ratio has told me more about a partner’s real contribution than any conversion count, and it is the number partners are least keen to discuss.

None of the three requires new tooling. All three require that your tracking is actually intact, which is a much less safe assumption than it sounds — affiliate tracking breaks quietly, and payout day is the wrong time to find out covers the failure modes that make these numbers lie before you ever get to interpret them.

Why platform defaults are not neutral

Every platform default encodes a commercial position, usually the platform’s own.

Look at what the defaults actually are. In Google Ads, per Google’s conversion window documentation, a new conversion action defaults to a 30-day click-through window, configurable from 1 up to 30, 60 or 90 days depending on the conversion source. The engaged-view window defaults to 3 days and the view-through window to 1 day, both adjustable to 30. On Meta, the default for campaigns optimising to website conversions is a 7-day click alongside shorter engage-through and view-through windows.

Then look at the other end of the spectrum. Amazon Associates runs one of the shortest windows in the industry — a 24-hour cookie, extended only if the customer adds the item to their cart within that day, in which case the purchase can still credit up to 90 days later, and only for the items placed in the cart during that original session.

Those are three completely different commercial philosophies presented as configuration. Amazon’s window is short because Amazon has demand of its own and does not need to pay you for it. A platform selling you media has every reason to default wide. Neither is lying. Both are negotiating, and one of them has already won because you never opened the setting.

There is one more thing in Google’s documentation worth holding on to, because it changes the timing of any negotiation: window changes apply only going forward. Shorten a 30-day window to 10 and the 10-day rule applies to conversions recorded from that day on. Past conversions are not restated. Which means you cannot quietly fix a bad window retroactively, and it means a partner who wants the change made before a big sale period is asking for something with a specific value they have probably already calculated.

The window is one term in a set of four. Never move it alone.

Never concede a window extension on its own, because the window is one of four interlocking terms and moving one without the others is how you pay twice.

The four:

1. Window length — how long after the touch a conversion still credits.
2. The validation or reversal window — how long you retain the right to claw back a credited sale for a return, a cancellation, a chargeback or a fraud finding.
3. The deduplication rule — what happens when two partners both have a live claim on the same order, and which position wins.
4. The rate, including tiers and any new-customer differential.

These trade against each other cleanly, and the trades are where the actual negotiation lives.

Give a partner 30 days instead of 7, and take a longer validation window in exchange — a wide credit window with a short reversal window is the single worst combination to sign, because it maximises the volume you pay on and minimises your right to correct it. Give 30 days, and take a new-customer differential: full rate on first-time buyers, reduced rate on repeats. Give 30 days to genuine content partners, and simultaneously tighten the dedup rule so that a coupon site landing at checkout cannot outrank an introducer who did the work on day one.

That last one deserves saying plainly. In most default configurations the last touch wins, which means a longer window given to everyone hands the largest gain to the partner closest to the checkout button. If you extend the window as a blanket policy, you are usually paying more to the partners who contributed least. The extension has to be paired with a dedup change or it inverts your own intention.

How to write it into the contract

Put the window in the commercial terms next to the rate, not in a technical appendix, and name all four terms in the same clause.

What that looks like in practice — described rather than drafted, because your counsel should write the words:

• State the window in days and name the trigger. Days from a qualifying click, defined. Not “standard industry window”, which resolves to whatever the network’s default happens to be on the day of the dispute.
• State the validation period and what may be reversed within it. Returns, cancellations, chargebacks, duplicate orders, orders failing a fraud check, orders placed by the partner’s own staff. Silence here defaults to the network’s terms, which were not written for you.
• State the deduplication rule explicitly, including how your owned channels are treated. If your email and organic traffic are eligible to win a contested order, say so. Most contracts are silent, and silence is a decision that goes against you.
• State what happens to in-flight touches when the window changes. Because changes are forward-only in most systems, a mid-month change creates a genuinely ambiguous cohort. Decide in advance who owns it.
• Give both sides a review right at a fixed cadence. A quarterly review clause turns “we need to talk about your window” from an accusation into a diary entry. This is the same principle as putting a quarterly access review in an agency contract, and it works for the same reason.
• Tie the window to a performance floor, not to tenure. A partner keeps the wider window while reversal rate and new-customer share stay inside agreed bands. This is the clause that lets you be generous without being permanently exposed.

If you are on the other side of this table — choosing programmes to promote rather than running one — the same four terms are what you should be reading before you join anything. The checklist for choosing an affiliate programme covers the partner-side view, and it is worth reading both directions before a negotiation.

The conversation, in order

Run the renegotiation in a fixed sequence, because the order determines whether you are discussing evidence or trading opinions.

1. Ask for the lag data before you respond at all. “Send me your time-to-conversion distribution for the last full quarter.” A partner with a real case has this and will send it. A partner testing you will send an anecdote about a customer who bought three weeks later.
2. Bring your own overlap number. Model the redistribution first. Walking in with “extending this window moves credit on roughly this proportion of orders, most of which currently credit elsewhere” ends the accuracy framing permanently and moves the conversation to price.
3. Name the trade before they name a number. “Thirty days works, paired with a longer validation window and a new-customer rate.” Concede the thing they asked for, in the same sentence as the thing you need.
4. Agree a review date and the bands. What reversal rate, what new-customer share, reviewed when.
5. Change one term, then wait a full purchase cycle. Two simultaneous changes make the result uninterpretable. This is the same discipline as never changing a tag and a tracking configuration in the same week.
6. Write down what the numbers looked like the day before the change. Nobody does this and everybody needs it. See the next section for why.

What to do when a partner insists on a window you cannot afford

When the window they need is genuinely wider than your margin supports, change the shape of the deal rather than the window.

Options, roughly in order of how often they work:

• Tier the commission by time-to-conversion. Full rate inside 7 days, reduced rate from 8 to 30. This is the honest expression of what a longer window is worth: something, but less. It is also the offer that separates partners who want fair credit from partners who want a raise.
• Pay a flat placement fee plus a short window. For discovery-shaped partners — content, newsletters, one-off influencer posts — the fee compensates the introduction directly, and the short window stops it being paid for twice.
• Differentiate on new customers only. Wide window on first-time buyers, narrow on repeats. Cleanly aligned with what you are actually buying.
• Exclude branded search from the wider window. If a partner bids on your own brand terms, a wide window is close to pure leakage. Carve it out explicitly.
• Offer the wider window as a time-boxed pilot with an agreed measurement plan. One quarter, defined metrics, an explicit end date rather than an automatic renewal. Most window extensions that turned out badly for me became permanent by default rather than by decision.

And sometimes the answer is no, and the partner leaves. That is a real outcome and it is survivable. A partner whose volume is only profitable under an allocation rule you would not otherwise choose was not profitable. It just looked that way.

The measurement trap: a wider window makes everything look better at once

The day after you widen a window, every partner’s conversion count goes up, your reported blended ROAS improves, and none of it means anything.

This is the trap that catches people who did everything else right. You made a careful, negotiated change. Then you looked at the numbers the following month and they were better, so you concluded the change was good. But a wider window mechanically increases attributed conversions across the board, because more historical touches are now eligible. Nothing about the business changed. The counting changed.

Three defences, all cheap:

Snapshot the before. Export the full set of per-partner metrics — conversions, reversal rate, new-customer share, blended cost of sale — on the day before the change. Not a summary. The export. This costs ten minutes and it is the only version of the baseline that will still exist in three months.

Judge the change on unattributed totals. Total orders and total revenue don’t care about your allocation rule. If total orders are flat and attributed conversions rose 20%, you have bought relabelling, not growth. That comparison is the entire test, and it takes one line.

Never compare across a window change. A pre-change month and a post-change month are different units of measurement wearing the same name. If you must report a trend across that boundary, say in the report that the boundary exists. The habit of stating which measurement regime a number came from is the same one that stops Search Console numbers quietly misleading you — in both cases the number is correct and the comparison is not.

The broader version of this discipline — deciding what a metric is for before you optimise against it — is the spine of the performance marketing playbook I actually use. Attribution windows are just the place where the cost of getting it wrong is easiest to measure and hardest to notice.

FAQs

Is a longer attribution window more accurate?

No. It is more generous to earlier touches. Accuracy would require knowing what actually caused a purchase, which no window can tell you. A window is an allocation rule, and the honest question is not which one is true but which one you want to pay against. Pick the one that matches your real time-to-conversion distribution, then treat it as a commercial position rather than a measurement.

What is a reasonable attribution window for an affiliate programme?

The one that covers the bulk of your actual conversion lag, which you should measure rather than benchmark. Industry norms range from Amazon’s 24 hours to 90 days on many SaaS programmes, and that spread exists because the underlying purchase behaviour genuinely differs. If most of your conversions land inside a couple of days, a long window is buying liability rather than fairness.

Does changing the conversion window affect historical data?

Not in Google Ads. Google’s documentation states that window changes apply only going forward — shorten a 30-day window to 10 days and the shorter rule applies to conversions recorded from that day onward, with past conversions left as recorded. Practically, this means you cannot retroactively repair a window you regret, and it means the timing of any change is itself negotiable value.

Who actually loses when an affiliate window is extended?

Usually your own owned channels, and any partner positioned earlier in the journey than the one whose window widened. Email, organic and direct traffic get deduped out of contested orders by paid touches with wider eligibility. Because those channels do not send invoices, the loss shows up as a rising blended cost of sale with no obvious cause.

Should the reversal window match the attribution window?

They serve different purposes, so they need not match — but the reversal window should never be materially shorter than the attribution window. A wide credit window paired with a short reversal window means you pay on the maximum possible volume while holding the minimum possible right to correct it. That combination is the most expensive thing you can sign, and it is common because the two terms are usually negotiated by different people at different times.

How do I model the impact before making the change?

Use the comparison tooling already in the platforms. Meta’s Compare Attribution Settings, in the Columns dropdown in Ads Manager, redistributes conversions across windows on data already collected without altering your live configuration. Google Ads exposes days-to-conversion reporting for the same purpose. Between them you can price the change on historical data, which is a much stronger position than agreeing first and measuring after.

A partner says their conversions are not being credited properly. Is that a tracking problem or a window problem?

Rule out tracking first, because the two look identical from the partner’s dashboard and only one of them costs you money to fix. Missing sub-IDs, a broken postback, a redirect stripping parameters and consent-blocked tags all present as under-credited conversions. Ask for the lag distribution: if their conversions are landing inside your existing window and still not crediting, it is a tracking fault, and extending the window would have hidden a bug behind a payment.

Key takeaways

• An attribution window decides who gets paid, not what happened. It is a commercial term.
• A wider window rarely finds new sales. It relabels existing ones, often away from your owned channels.
• Price it with three numbers first: time-to-conversion distribution, overlap rate, new-customer share.
• Platform defaults are commercial positions. Amazon’s 24 hours and a 30-day media default are both arguments.
• Never move the window alone. Trade it against the validation window, the dedup rule and the rate.
• A wide credit window with a short reversal window is the worst pair to sign.
• Extending the window for everyone pays the checkout-adjacent partners most. Pair it with a dedup change.
• Window changes are forward-only, so you cannot fix a regret retroactively. Timing is value.
• Snapshot every per-partner metric the day before you change anything.
• Judge the result on total orders, not attributed conversions. Attributed conversions always rise.