On 1 August, a reader in Egypt — Hossam — sent us a short, precise email. It is worth quoting almost in full, because it is close to a perfect bug report:
I noticed a difference in the current price listed for the Big Mac in Egypt on your platform.
- Currently listed price: 125 EGP
- Actual current price: 170 EGP
- Location/Market: Egypt (Standalone Big Mac burger)
- Source: Official McDonald’s Egypt Delivery Website (mcdelivery.eg)
Given recent local menu price adjustments, the 125 EGP entry is currently outdated.
He was right about what we were showing. He was right that it was stale. And working out why it was stale turned out to be more interesting than the correction itself.
Three numbers, all defensible
| Figure | Source | What it represents |
|---|---|---|
| E£125 | The Economist, January 2026 edition | What we were showing |
| E£145 | The Economist, July 2026 edition | The new official figure |
| E£170 | McDonald’s Egypt delivery menu, August 2026 | What a customer pays today |
Hossam caught us at an awkward moment: The Economist had just published its July edition — with Egypt revised up to E£145, a 16% local-currency increase — and we had not yet ingested it. That part was on us, and we have fixed it, along with the underlying cause.
But even after the update, a gap remains: E£145 official versus E£170 on the menu. That gap is not an error. It is the structure of the index showing through.
Why an index and a menu board disagree
The Big Mac Index works because all 54 countries are priced on the same day using the same method. That synchronisation is the entire source of its comparative power. The July 2026 edition reflects prices sampled around 1 July.
A delivery menu reflects today.
In a country where inflation is running hot, a few months of separation between “the same day everywhere” and “right now here” produces exactly the kind of spread Hossam found. Egypt’s local Big Mac price rose 16% in the six months the index did capture; it is entirely plausible it moved another 17% in the weeks after the sampling date.
So we had a choice, and it is worth being explicit about it:
Option A — publish E£170. More current for Egypt. But it silently breaks the comparison. Egypt would be measured in August while the other 53 countries sit at 1 July, and Egypt would look more expensive than it should relative to everyone else. A number that is fresher but incomparable is not obviously better.
Option B — publish E£145, and record E£170 openly. Keeps the cross-country arithmetic honest, and treats the divergence as information rather than noise.
We chose B. Egypt shows E£145 ($2.87) in the index, and the Egypt country page carries an editorial note recording the E£170 observation, its source, and its date — credited to Hossam.
We think the gap is more useful published than hidden. “The official index says $2.87, the menu today says roughly $3.36” tells you something real about Egyptian inflation that neither number tells you alone.
What his email actually fixed
The correction we shipped is larger than one country.
Chasing why Egypt was stale, we found that our data fetcher had an off-by-one in its edition selector. It decided whether to look for the January or July file using a month comparison that was wrong by one — so in July it kept reaching for the January file, found it, and stopped. The January file always exists, so the fallback never triggered and nothing ever failed loudly.
The site had been sitting on January data while a July edition was available, and would have kept doing so.
We also found a second, quieter problem: the downloadable dataset on our data page had drifted even further out of date than the site itself — it was still serving figures from January 2025. It was a one-off hand-built file that nothing was responsible for regenerating. It is now generated from the same source as the live site on every build, with a guard that refuses to publish data older than what it replaces.
One reader emailing about one burger surfaced a pipeline bug affecting all 54 countries and a stale public dataset. That is a good trade for the cost of reading an email.
Thank you, Hossam.
Send us corrections — we read all of them
If you live somewhere in the index and the number looks wrong, please tell us. What makes a report immediately actionable is exactly what Hossam did:
- The country and what we currently show
- The price you observed, and whether it is the standalone burger (not a meal or combo)
- A source — the official McDelivery site for your country is ideal, a photo of the menu board works too
- The date you saw it
Send to [email protected].
On credit and privacy. Reports that check out get credited on the country page, as Hossam’s is. By default we publish first name only — we do not put anyone’s full name on a public page, indexed by search engines, just because they helped us. If you would prefer something else, say so and we will use it: full name, first name and initial, a handle, a link to your site, or no attribution at all. If you say nothing, we stay at the most private option.
What comes next
We are building toward a data operation that is more than a semi-annual import:
- Reader price reports. Already live, informally, through the address above. Verified reports become editorial notes on country pages, alongside the official figure rather than replacing it.
- Our own editorial research. We already publish independently researched figures for markets The Economist aggregates or skips — the eurozone breakdown is the clearest example, where a single “Euro area” row hides a 25%+ spread between member states.
- Comments on articles and country pages. Coming soon, so reports and local context can be posted publicly instead of arriving one at a time in our inbox. Reader observations and editorially verified figures will stay visually distinct — community knowledge is valuable precisely when you can see where it came from.
The Economist gives us a rigorous, synchronised skeleton twice a year. Readers standing in front of actual menu boards can tell us what happens in between. Those are different kinds of information and we intend to publish both, clearly labelled.
Egypt’s index figure was updated from E£125 to E£145 on 31 July 2026 with The Economist’s July edition. The E£170 observation is recorded as an editorial note, credited to Hossam, sourced from mcdelivery.eg on 1 August 2026. See the July 2026 data update for the full six-month analysis.