# How We Measure Project Success: The KPI Agreement We Make Before Development

> Bang Digital agrees project KPIs with the client during discovery: baseline, 30- and 90-day targets, method and owner. The framework and the one-page format.

Published: 2025-09-30 · Process · Bang Digital · https://bang-digital.com/en/blog-how-we-measure-project-success.html

Bang Digital defines project success before development starts. During discovery the client and the team agree on a short list of KPIs, and each KPI gets a baseline value, a 30-day target, a 90-day target, a measurement method and an owner. The agreement fits on one page and is used for the rest of the project to decide what enters the scope.

## Key takeaways

- A KPI without a recorded baseline cannot show change, so the baseline is captured before the first release.
- KPIs fall into four groups: business, conversion, technical and engagement; business KPIs are owned by the client, technical KPIs by Bang Digital.
- Google's Core Web Vitals thresholds for a good page are LCP ≤ 2.5 s, INP ≤ 200 ms and CLS ≤ 0.1 at the 75th percentile; INP replaced FID on 12 March 2024.
- A feature request is scoped only if it moves an agreed KPI; otherwise it goes to the backlog until the 90-day review.

## Launch as the finish line

Most digital projects are accepted at launch. Acceptance confirms that the agreed features work, but it records nothing about the effect on the client's business. Three months later neither side can tell whether the investment paid off, because nobody wrote down where the numbers started.

A KPI agreement fixes the starting point. A later figure without a baseline is an anecdote; the same figure measured against a baseline is a change that can be attributed and discussed.

## Place of the agreement in the project

Every Bang Digital project starts with discovery and domain modelling, and discovery is included in the project price. The KPI agreement is one of the discovery outputs, alongside the domain model. Development begins after both sides sign it.

## Effect of agreed KPIs on project decisions

| Situation | Without agreed KPIs | With agreed KPIs |
|---|---|---|
| Design review | Decided by taste | Checked against the agreed conversion target |
| Feature request | Debated on opinion | Checked against the KPI it is meant to move |
| Launch | End of the project | Start of the 30- and 90-day measurement |
| Post-launch work | Driven by the latest request | Driven by the metric furthest from its target |

## KPI groups

KPIs are grouped by who can influence them. Business KPIs depend on the client's sales and pricing, technical KPIs depend on the development team, and conversion and engagement KPIs depend on both.

### Business KPIs

| KPI | Measurement method | Owner |
|---|---|---|
| Qualified leads per month | CRM, lead source field | Client |
| Revenue from organic web traffic | UTM-tagged sessions linked to deals | Client |
| Sales cycle length | CRM stage timestamps | Client |
| Average deal size or average order value | CRM or e-commerce back office | Client |

### Conversion KPIs

| KPI | Measurement method | Owner |
|---|---|---|
| Homepage to contact form conversion rate | Analytics events | Shared |
| Landing page conversion rate | Analytics events, target set per campaign | Shared |
| Cart abandonment rate | Checkout funnel report | Shared |
| Form completion rate | Form start and submit events | Shared |

### Technical KPIs

| KPI | Target | Owner |
|---|---|---|
| Core Web Vitals | LCP ≤ 2.5 s, INP ≤ 200 ms, CLS ≤ 0.1 at the 75th percentile | Bang Digital |
| Lighthouse Performance score | 90+ on mobile, 95+ on desktop | Bang Digital |
| Mobile load time | Under 2 s on a 4G connection | Bang Digital |
| Uptime | 99.9% minimum, monitored after launch | Bang Digital |

The Core Web Vitals thresholds are Google's definition of a good page experience and are measured on real users. Interaction to Next Paint (INP) replaced First Input Delay (FID) as a Core Web Vital on 12 March 2024, so checklists that still list FID are out of date. Lighthouse is a lab test on a single simulated device; it is used during development, while Core Web Vitals are the acceptance criterion after launch.

### Engagement KPIs

| KPI | Measurement method | Owner |
|---|---|---|
| Bounce rate on key pages | Analytics, definition fixed in the agreement | Shared |
| Average session duration | Analytics | Shared |
| Pages per session | Analytics, for multi-product and content-heavy sites | Shared |
| Return visitor rate | Analytics, for products and platforms | Shared |

Engagement metrics are indirect signals and are read together with conversion KPIs. Analytics systems define bounce differently, so the agreement names the tool together with the definition.

## Agreement format

The agreement is a single table with six columns: KPI, baseline, 30-day target, 90-day target, measurement method and owner. The client fills in the business KPIs, the team fills in the technical KPIs, and both sides sign the document. The example below uses illustrative values.

| KPI | Baseline | 30-day target | 90-day target | Method | Owner |
|---|---|---|---|---|---|
| Qualified leads per month | 12 | 15 | 20 | CRM, lead source field | Client |
| Contact form conversion, % | 0.8 | 1.2 | 1.8 | Analytics events | Shared |
| LCP at the 75th percentile, s | 3.9 | 2.5 | 2.5 | Field data | Bang Digital |

## Scope control

A feature request is checked against the agreement. If the feature moves an agreed KPI, it is estimated and scheduled. If it moves none, it goes to the backlog and is reviewed at the 90-day checkpoint together with the measured results.

## Limitations

A new product has no baseline. In that case the first 30 days after launch establish it, and targets are fixed at the first review. Business KPIs also depend on factors outside the project, such as pricing, the sales team and seasonality, so the agreement lists these factors to keep the results interpretable.

## Principle behind the framework

Bang Digital earns when its clients earn. In some engagements part of the fee is tied to a described KPI or to a share of the result, and such terms require a baseline recorded before the work starts. The KPI agreement provides that baseline for every engagement, whatever the payment model.

Related reading: [How to Brief a Design Agency](https://bang-digital.com/en/blog-how-to-brief-a-design-agency.html), [Why Your B2B Website Doesn't Convert](https://bang-digital.com/en/blog-b2b-website-conversion.html), [Services](https://bang-digital.com/en/index.html#services).

## FAQ

### What is a KPI agreement in a web development project?

A one-page table agreed by the client and the agency before development. For each KPI it records the current baseline, the 30-day and 90-day targets, how the value is measured and who owns it.

### When does Bang Digital agree KPIs with the client?

During discovery, which starts every Bang Digital project and is included in the project price. Development begins after the agreement is signed.

### What are good Core Web Vitals values?

According to Google's web.dev, a page is good when LCP is at most 2.5 seconds, INP at most 200 milliseconds and CLS at most 0.1, measured at the 75th percentile of real page loads.

### How are KPIs set for a new product without historical data?

The first 30 days after launch are used to establish the baseline. Targets are fixed at the first review instead of before development.

## Sources

1. [How the Core Web Vitals metrics thresholds were defined](https://web.dev/articles/defining-core-web-vitals-thresholds), web.dev (Google)
2. [Interaction to Next Paint becomes a Core Web Vital on March 12](https://web.dev/blog/inp-cwv-march-12), web.dev (Google)