Baseline: How to Prepare Your Benchmark Before Launch

Why your baseline determines the measurable success of your project

Without a baseline, no impact measurement is possible

67% of redesign projects never measure their ROI because reference data was not collected before launch. Without an initial snapshot, you cannot compare “before” and “after” in a factual way.

It is essential to define clear and measurable goals (KPIs) from the strategy and preparation phase. This step determines your entire ability to prove the value of your project.

The baseline protects you from perception bias

Teams often overestimate the real improvement because they poorly remember the initial situation. A documented baseline neutralizes this bias by setting objective numbers.

It also helps you detect seasonal variations: if you launch in January and compare with December, you risk confusing project effect with calendar effect.

It turns your project into a credible case study

It is recommended to establish reference metrics: current traffic, conversion rate, and SEO positions before any redesign. A benchmark shows that a 20% increase in traffic and 15% in conversions is a realistic target.

These numbers mean nothing without a baseline: you need to prove where you started to showcase where you end up.

The essential data to capture in your baseline

Traffic and acquisition sources

Collect for a minimum of 2 to 4 weeks (ideally 3 months to smooth out seasonality):

• Total sessions and unique users
• Traffic by channel (organic, direct, referral, social, paid)
• Page views and overall bounce rate

These metrics show you whether your redesign improves or degrades the visibility and attractiveness of your site.

SEO performance and rankings

Complete snapshot of your organic rankings:

• Number of keywords ranked (top 3, top 10, top 50)
• Monthly organic traffic
• Referring domains and active backlinks

A poorly prepared redesign can cause your SEO traffic to drop by 30% or more if you don’t properly map your URLs and redirections.

Conversion and engagement

For each important business objective:

• Overall conversion rate and per landing page
• Average conversion value
• Time on site and navigation depth

Google Analytics 4, Hotjar, or Matomo are sufficient for most projects to evaluate your site with powerful analytics tools.

Technical performance

Measure loading speed before any modification:

• Core Web Vitals (LCP, FID, CLS) via PageSpeed Insights
• Server response time (TTFB)
• Weight of main pages

It is essential to evaluate your starting point in terms of speed and then set realistic performance goals. Without this technical baseline, you cannot prove UX improvement.

The fatal trap: a baseline that is too short or too broad

Less than 7 days of data = unreliable baseline

One week of data rarely captures the normal variations in your activity. If you measure during an exceptional peak or dip, your baseline will be skewed.

Our recommendation: 2 weeks minimum for an express baseline, 1 month ideal, 3 months to eliminate any seasonal effect.

Too many KPIs kill the measurement

A redesign requires thorough preparatory work. But be careful: listing 50 indicators dilutes your attention and complicates post-launch reading.

Focus on 8 to 12 KPIs maximum, directly tied to your business objectives: traffic, conversion, SEO, speed. The rest is noise.

Forgetting the external context

Your baseline must include external events that influence your metrics: active paid campaigns, business seasonality, competitor actions, Google algorithm changes.

Note these elements in a separate document: they will help you interpret gaps between baseline and post-launch.

Concrete case: an e-commerce redesign baseline

Context and objectives

An e-commerce company documented its own replatforming methodology. The company started by evaluating its speed starting point before any technical modification.

Their baseline included:

• Core Web Vitals on 50 strategic pages
• Mobile vs desktop conversion rate
• Median loading time by category

Collection duration and scope

Collection lasted 4 weeks to capture two complete cycles of weekly promotions. The company deliberately excluded Black Friday periods to avoid skewing the reference.

This approach allowed them to set achievable performance targets: reduce LCP from 3.2s to 2.1s and increase the mobile conversion rate by 12%.

Measurable post-launch results

Thanks to this rigorous baseline, the company was able to demonstrate:

• A 34% improvement in LCP
• An 18% increase in mobile conversion rate
• Project ROI validated in 6 months

Without the initial snapshot, these numbers would have had zero credibility.

How to organize your baseline collection in 1 to 2 weeks

Week 1: extraction and centralization

Set up your measurement tools if not already done:

• Google Analytics 4 with conversion goals activated
• Google Search Console for SEO
• PageSpeed Insights or GTmetrix for performance

Export data from the last 3 months (or at minimum the last 30 days). Centralize everything in a shared Google Sheet or Looker Studio.

Week 2: validation and documentation

Verify the consistency of your data:

• Compare GA4 figures with those from your CRM or e-commerce tool
• Check that peaks/dips correspond to known events
• Identify and document anomalies (bug tracking, exceptional campaigns)

Write a “Baseline [Project Name] - [Date]” document that lists:

• The 8 to 12 selected KPIs
• Their average value over the period
• External context (seasonality, active campaigns)

Concrete action: create your baseline dashboard

Use this template to structure your baseline:

Share this file with all project stakeholders before launch.