Festival lag is not a rounding error

Grocery and beauty sales around Hari Raya and Chinese New Year often arrive after the panels come down. Credit rules that ignore that lag donate store traffic to the next digital burst.

Brand calendars in Malaysia are not evenly spaced Tuesdays. Hari Raya shopping starts before the public holiday. Chinese New Year baskets move in a short, bright window. 11.11 is a marketplace event with its own voucher physics. If your credit window is always seven days, you will keep handing delayed store sales to whatever digital burst is on air when the customer finally pays.

In one grocery post-mortem we ran, door counts rose five to nine days after an outdoor upweight, while tagged marketplace orders moved in the same week as the voucher. Last-click gave the marketplace both. A lag sentence — “store traffic may be credited to outdoor for nine days after the flight, marketplace orders stay on their tag unless a unique outdoor code is present” — changed the table without anyone pretending the voucher was imaginary.

Write the lag before you see the numbers. If you choose the lag after you see which channel you prefer, the readout becomes a negotiation about taste. Festival lag belongs in the method note next to the lookback, in ordinary language, initialled by brand.

Not every category needs nine days. A same-week food delivery burst may honestly be a same-week story. The mistake is using one window for festive grocery and for a Tuesday app-install flight as if they were the same object.