Your BFCM Numbers Will Not Compare to Last Year, Here Is Why

BFCM is roughly twelve weeks away and most brands are thinking about stock, offers and creative. There is a measurement problem sitting underneath all of it that almost nobody has factored in. Conversion tracking on Shopify changed on 26 August, and if your comparison for this season is last season, you are about to compare two periods that were measured differently. The revenue will be real. The attribution will not be comparable.

What changed and why it matters now

On 26 August 2026, script tags on the Thank you and Order status pages were sunset for non-Plus stores. Anything sitting in the Additional Scripts field stopped running, which for most stores meant conversion tracking.

Two possible states for your store today. Either you rebuilt tracking as web pixels or vendor apps, in which case your data is flowing again but through a different mechanism than last year. Or you did not, in which case there is a hole in your data that started in late August and is still open.

Both states break a year-on-year comparison, and the second one breaks your BFCM decision-making in real time.

Check whether you are actually recording conversions

Before anything else, confirm the basics. This takes ten minutes and a refunded test order.

Place a real order. Watch for the conversion in Google Ads and in Meta Events Manager, and check the value and currency are correct rather than just confirming something fired. Then compare your platform-reported conversions for the last week against actual orders in Shopify for the same period.

If the platforms are reporting materially fewer conversions than Shopify recorded orders, you have a gap, and every bidding decision between now and BFCM is being made on it. Our diagnostic for that covers the four causes in the order to check them.

The stores most at risk

Three situations where this is more than a reporting inconvenience.

Brands spending heavily on paid acquisition, because bidding decisions compound. Two months of slightly wrong conversion data does not produce a slightly wrong outcome, it produces campaigns optimised toward the wrong audiences with budget already spent.

Brands who never touched the Additional Scripts field after the deadline, because nothing told them to. The store looks healthy, orders arrive, and the gap only becomes visible when somebody compares platform conversions against Shopify orders, which is not a routine anybody runs.

Brands who changed agency or freelancer this year, because the person who originally pasted those tags is gone and nobody currently working on the account knows what was in there. That is the case where the gap is most likely to still be open today.

Why last year is not a clean baseline

Even with tracking working perfectly today, the comparison is not like for like.

Last November your conversions were recorded by a script running on the Thank you page. This November they are recorded by a web pixel running in a sandboxed environment. The mechanisms differ in what they can see, when they fire and how reliably they attribute. A small difference in capture rate looks exactly like a small difference in campaign performance, and you will not be able to tell them apart from the numbers alone.

The honest position is that platform-reported ROAS for BFCM 2026 is not directly comparable to BFCM 2025. Say that out loud before the season rather than arguing about it in December.

The number that stays honest

There is one comparison that survives all of this, and it is the one to build your review around.

Total revenue against total ad spend, taken from Shopify and from your ad platform billing, is unaffected by attribution mechanics. It does not tell you which campaign worked, but it tells you whether the season worked, and it is measured the same way it was last year.

Pull that number for BFCM 2025 now, before the season, so you have a baseline you trust. Blended performance is a blunt instrument and right now it is the sharpest one you have.

What to do in the next four weeks

• Verify conversions are recording, with a real order, checking value and currency.
• Reconcile platform conversions against Shopify orders for the last 30 days and write down the gap.
• Annotate the 26 August change in your analytics and ad accounts, so whoever reads the data later sees why the line moves.
• Pull your blended baseline from last BFCM: revenue, spend, orders, AOV.
• Fix any gap now, not in November. Smart bidding needs conversion history to work with, and a campaign entering BFCM with three weeks of clean data will perform worse than one with three months.

That last point is the one with a deadline attached. Automated bidding learns from recorded conversions. If your tracking has been broken since August and you fix it on 20 November, those strategies go into peak season with almost no history.

Set up the report before you need it

The worst time to work out how you will measure BFCM is during BFCM. Build the view in September while nothing is urgent.

Four lines are enough for most Indian D2C brands. Orders and revenue straight from Shopify, which is your ground truth. Total ad spend from platform billing rather than from the platforms' own reporting. Blended cost per order, which is spend divided by orders. And your COD share, because a season with a heavier COD mix will look better on revenue and worse once RTO lands in December.

That last line is the one brands skip and then argue about in January. A BFCM that broke records on gross revenue and shipped a much higher proportion of COD can be a worse season than the previous one once returns settle, and you will not see it until six weeks later.

Plan for a December correction

Whatever your season looks like on 1 December, it is not the final number, and treating it as one leads to bad decisions in January.

Returns and RTO arrive weeks after the orders do. Refunds land against revenue you already counted. If you set next year's budget from a gross November figure, you are planning against money you did not keep.

Put a date in the calendar for mid-January to redo the season's numbers net of returns and refunds. Compare that to the same net figure from last year, which is the only genuinely honest year-on-year comparison available given the tracking change. It takes an hour and it is the difference between knowing how the season went and believing a headline.

Do not change tracking during the season

Whatever state you are in, get it stable by early November and then stop.

Changing a pixel, adding a new analytics tool or switching attribution settings during BFCM creates a discontinuity in your highest-volume period, which is the worst possible time to have data you cannot trust. If something is broken in the last week, weigh fixing it against the reporting mess of a mid-season change.

The exception is a total failure, where no conversions are recording at all. That is worth fixing immediately regardless of timing.

Will my BFCM data be comparable to last year?

Not directly, at the campaign and channel level, because the mechanism recording conversions changed in August. Blended revenue against blended spend remains comparable, which is why that should be your headline measure this season.

How do I check whether my conversion tracking works?

Place a real order and confirm it appears in Google Ads and Meta with the right value and currency. Then compare platform-reported conversions against Shopify orders for the same period. A persistent gap means something is not recording.

Is it too late to fix tracking before BFCM?

No, but the window is closing. Automated bidding uses conversion history, so a fix in September gives campaigns two months to learn before peak. A fix in late November gives them days.

Should I add new tracking tools before BFCM?

Only if you can install and validate them by early November. Anything added later creates a discontinuity in your most important trading period, and the insight is rarely worth the confusion.

What should I report to my team this year?

Lead with blended revenue and spend, because that is comparable to last year. Present channel-level attribution as directional rather than exact, and note the August change alongside it so nobody builds a plan on a difference that is really a measurement artefact.

Get your measurement checked before peak

Free check. Email hello@exactwhy.com with subject "BFCM tracking" and your store URL. We check whether conversions are recording, compare platform numbers against your Shopify orders, and tell you whether you have a gap. We respond within 4 hours, and September is the right month for this.

Paid work, Rs 25,000 to Rs 1 lakh. Rebuilding tracking properly on supported surfaces, verifying against real orders across payment methods, and setting up the blended reporting you will actually use in December.

Ongoing Shopify development, Rs 20,000 to Rs 50,000 a month. Including the monthly verification that keeps this from happening again.

Everything else on your BFCM checklist can be fixed during the season. Measurement cannot, because the data you fail to collect in November does not come back. Our analytics setup notes cover the baseline this sits on.