Beside every Performance Trends chart sit two small toggles: **−− vs previous**, and **Values / % change**. They are easy to ignore and they change what the chart is telling you.

[Watch the walkthrough](https://kb.trackiq.com/kb-assets/kbvideo-values-pct-explainer-22cb10c7.mp4)

*Prefer to watch? Sixty-five seconds on when each toggle is the honest one.*

## **What each one does**

![The controls sit at the top right of every Performance Trends chart](/kb-assets/shot-adv-campaigns-view-77ace2.png)

**vs previous** overlays the preceding period as a dashed line. Same length, immediately before — so a 28-day view compares against the 28 days before it.

**Values** plots the actual numbers. **% change** plots movement instead.

They combine, and the combination is the point.

## **Values, with vs previous**

The default, and right most of the time.

You see this period solid and last period dashed, in the same units. **Scale is preserved**, so you can tell whether a change is large or merely visible — a spike that looks dramatic in isolation often turns out to be a normal Tuesday once last month is drawn beside it.

Use it for: *“are we up or down, and by how much?”*

## **% change**

Plots the movement rather than the level, which does two useful things.

**It makes small series comparable to large ones.** A campaign spending $200 and one spending $20,000 cannot share a y-axis in Values — the small one is a flat line at the bottom. In % change they are directly comparable.

**It surfaces the thing you actually care about**, which is usually the direction rather than the amount.

Use it for: *“what moved most?”*

The trade is that **% change hides scale**. A 300% rise on $40 and a 3% rise on $400,000 look nothing alike in reality and can look similar here. Check the tile above before acting.

## **A rule of thumb**

| Question | Setting |
|---|---|
| Are we up or down? | **Values** + vs previous |
| Which of these moved most? | **% change** |
| Is this spike real? | **Values** + vs previous |
| Comparing very different sizes | **% change** |
| About to quote a number | **Values** |

## **The tiles use it too**

The **vs prev** figure on each headline tile is the same comparison in one number — *“▲23.9% vs prev”* means this period against the one immediately before.

Two cautions there:

**Percentage points versus percent.** When the metric is *itself* a percentage — ACoS, CTR, conversion — a change from 40% to 44% is **4 percentage points**, not a 4% rise. It is a 10% rise. Getting this backwards over-reports or under-reports every efficiency change.

**Direction is not quality.** ACoS falling is good; impressions falling usually is not. The arrow colour tells you the direction, not whether to be pleased.

## **Granularity changes the comparison too**

**Day / Week / Month** sets the grain, and the comparison period follows it.

**Daily advertising data is noisy.** Weekday patterns make every daily chart look volatile, and a single quiet Sunday can read as a collapse. For anything longer than a fortnight, **Week** is usually the honest view.

## **The caveat that applies to all of it**

Whatever you set these to, **the last day or two of any period is still filling in** — Sponsored Products is credited over 7 days, Brands and Display over 14.

So a **vs previous** comparison ending today compares a settled period against an unsettled one, and will always flatter the past. If the comparison needs to be fair, end it a fortnight ago.

See [**My Ad Data Is Missing or Looks Wrong**](https://kb.trackiq.com/hc/knowledge-base/articles/my-ad-data-is-missing-or-looks-wrong) and [**Where Your Data Comes From and How Fresh It Is**](https://kb.trackiq.com/hc/knowledge-base/articles/where-your-data-comes-from).

## **Related**

- [**Date Ranges, Granularity and Comparing Against the Previous Period**](https://kb.trackiq.com/hc/knowledge-base/articles/date-ranges-granularity-and-period-comparison) — the comparison period itself.
- [**Analyzing Your Data**](https://kb.trackiq.com/hc/knowledge-base/articles/analyzing-your-data) — the screens this toggle sits on.