One number alone shows nothing — log it three times and it becomes a line

What this is

One of our published methods, written in plain language: what it can do, when to use it, what goes in and what comes out.

Why it matters

Most methods are published as papers or code. This one is written so you can decide whether it fits your problem before you invest time in it.

How to use it

Read the page top to bottom. If it matches your question, use the online tool - or subscribe and run it on your own data.

What you get

A clear answer on what the method does and does not do, plus a live curve from our own demand series. Free to read.

Free to readOnline tools from $5 per runSee it →

Demand curve read by this method — A live reading from our own demand series - the shape of the signal this method works on. 570 industries are tracked daily; this is one of them.

Our own data: city and industry curves built from our own records - 391 cities, 75 industry benchmarks (2026-10-08).
Data base: InfoGap own records - 391 Chinese cities x 8 dimensions, 213,208 city-industry rows, 40,499 POIs (central / lifechain, 2026-10-08).

Algorithm Handbook · one algorithm per page · plain language throughout

1In one line: what it does

One number logged once shows no problem; log it three times and it becomes a line, so whether it is rising or falling, and whether it has reached a turning point, is obvious at a glance.

2When to use it

These three things are probably happening to you right now:

You cannot say clearly whether foot traffic at the shop is going up or down.

What most people do: describe it from how the last few days felt.

Using it: record three scores (once a month, say); it joins them into a line and tells you whether this is "spike then fall back" or "steady deterioration".

You just made a change and want to know whether it helped.

What most people do: finish the change and stop there, then a few days later say from feeling that it "seems a bit better".

Using it: record once before the change, once after it, once again later — three points make a line, and you can see whether it is a "small rise" or "basically flat".

You look at the public industry trend pages, where every curve is labelled with its source, and you cannot tell whether you are on the same path.

What most people do: compare how they feel with how the industry feels.

Using it: record your own number three times in the same way and read it against the industry direction.

3What goes in · what comes out

Input: three scores for the same metric + the metric name (this is the exact set used in the real run)

Metric name — foot traffic
Run 1 — 40
Run 2 — 55
Run 3 — 38

What comes out

Output: the text it produced, not a single word changed

Data points: run 1: 40 / run 2: 55 / run 3: 38
Highest 55 / lowest 38 / average 44.3
Swing: 17
Trend call: run 2→3 sharp decline (-17); turning point: spike then fall back 🟠
Type: spike then fall back 🟠
Conclusion: foot traffic: 3 data points | 🟠 spike then fall back | highest 55 lowest 38 average 44.3 | ✅ curve generated

How to read it: it rose on the second run and fell back on the third, which is "spike then fall back". Don't stare only at the 38 of the third run and call it hopeless, and don't stare only at the 55 of the second run and call it fine — look at any one number alone and it will fool you. Within three points it only makes a trend call.

📈One chart: log it three times and it becomes a line

Log the same number three times and it will tell you itself whether it is climbing or falling.

4How to use it

There is no public calculator for this yet — the method above is the whole procedure; on this site the three numbers have to be keyed in by hand.

Pick one fixed metric name (foot traffic, revenue, number of people joining a group — any of them will do)
Record it three times at a fixed interval and write the three numbers down
Take the highest, the lowest and the average, and check how much moved between run 2 and run 3
Read the trend type and the turning-point note

5Who it's for

Owners who want to argue with numbers rather than feelings; people who just made a change and want to check whether it worked; people who look at industry trends and want to see where they stand.

6Common questions

Q: Why does it have to be three times?

A: The first is only a baseline, the second shows the direction, and only the third shows whether there is a turning point. One record shows nothing at all.

Q: How often should I record?

A: Any fixed interval will do — once a week or once a month. Don't record only when you happen to think of it; if the intervals are irregular the line means nothing.

Q: Where do the numbers come from?

A: Any number your shop is already tracking. The key is not to swap metrics back and forth, and not to rename it halfway through.

7Related algorithms

industry-vitality · is the industry itself rising or falling funnel-evaluate · which layer actually moved after the change demand-verify · is the demand still real ← Back to the Algorithm Handbook Handbook index

✓Why this scenario exists (evidence)

Why this scenario exists:

On the site's public trend pages, every industry curve is labelled with its source, and each of the 50 rows in the GEO opportunity table is also tagged "industry direction = rising".

In other words, industry-level curves are already being done by someone; the curve at the individual shop owner's level is the missing piece.

Source: the site's public trend pages, plus the GEO opportunity table (industry direction field).