First Click Attribution

Why this matters

First Click Attribution (FCA) assigns 100% credit to the first marketing interaction on a path to conversion. As a Marketing Analyst, you will use FCA to:

• Gauge which channels are best at discovery and acquisition (e.g., Paid Social vs. Organic Search).
• Allocate upper-funnel budget confidently for awareness campaigns.
• Benchmark new-market launches where you need to know what got people in the door.
• Run A/B tests on first-touch creatives and landing pages, then attribute outcomes consistently.

Good to know: FCA complements, not replaces, other models. Use it alongside last-click, time-decay, or data-driven models to triangulate decisions.

Concept explained simply

First Click Attribution gives all credit for a conversion to the first recorded touchpoint in the customer journey within your lookback window. If the first interaction was a Facebook ad and the customer later clicked email and converted, Facebook gets 100% of the credit.

• When FCA shines: measuring discovery effectiveness, early-stage campaigns, brand awareness, prospecting, new product/market entry.
• When FCA falls short: evaluating retargeting, conversion CRO, bottom-funnel channels; journeys where most value is created later.
• Lookback window: Only counts touches within a defined period before conversion (e.g., 30 days). The first touch inside the window gets credit.

Note on data quality: consistently use the same channel taxonomy and ensure deduped user IDs across devices where possible.

How to calculate First Click Attribution

1. Define your lookback window (e.g., 30 days) and conversion (purchase, signup, lead).
2. For each conversion, list all touches from the same user within the window, sorted by time.
3. Assign credit to the earliest touch in that list. That channel gets 100% credit.
4. Aggregate results by channel, campaign, or creative to get counts, revenue, and rates.

Worked examples

Example 1 — Simple multi-touch path

Path: Paid Social → Email → Direct → Purchase ($120)

FCA result: Paid Social gets 1 conversion and $120 revenue.

Example 2 — Lookback window effect

Events:

• Day -35: Organic
• Day -5: Paid Search
• Day 0: Purchase ($200)

With a 30-day lookback, Organic is outside the window, so Paid Search gets 1 conversion and $200.

Example 3 — Multiple conversions per user

User path:

• Day -7: Referral
• Day -2: Email
• Day 0: Purchase #1 ($80)
• Day +10: Email
• Day +12: Purchase #2 ($60)

FCA is per conversion:

• Purchase #1 credited to Referral (first touch in window before that conversion).
• Purchase #2 credited to Referral again if still within the window and no earlier first touch exists for that second conversion; otherwise, the earliest touch in-window before the second conversion gets credit. In this path, Referral remains the first touch in the 30-day window, so Referral gets both.

In practice: quick workflow

1. Collect events: user_id, timestamp, channel, is_conversion, revenue.
2. Filter to the lookback window per conversion.
3. Pick the earliest touch per conversion.
4. Aggregate to channel/campaign; compute conversion count, total revenue, and share.

Hands-on exercises

Everyone can do the exercises and take the quick test. Only logged-in users get saved progress.

Exercise 1 — Identify first-touch credit

Journeys (assume a 30-day lookback; treat Direct as a valid channel):

• A: Google Ads → Email → Purchase ($100)
• B: Organic → Purchase ($50)
• C: Facebook Ads → Direct → Purchase ($200)
• D: Referral → Email → Purchase ($80)
• E: Direct → Purchase ($40)

Task: Attribute 1 conversion and the full revenue to the first touch of each path. Provide totals by channel and revenue share.

• Deliverable: Channel → conversions, revenue, revenue %
• Timebox: 10 minutes

Exercise 2 — Spreadsheet implementation

Create a small sheet with columns: user_id, ts, channel, is_conversion (0/1), revenue.

Data to enter:

• u1, 2025-01-01 10:00, Paid Search, 0, 0
• u1, 2025-01-02 09:00, Direct, 0, 0
• u1, 2025-01-02 09:05, (blank), 1, 120
• u2, 2025-01-03 12:00, Social, 0, 0
• u2, 2025-01-05 12:30, (blank), 1, 80
• u3, 2025-01-04 08:00, Organic, 0, 0
• u3, 2025-01-08 09:00, (blank), 1, 150

Steps (Google Sheets or Excel):

1. For each conversion row, find the earliest ts for that user where ts ≤ conversion ts using MINIFS.
2. Lookup the channel at that earliest ts (XLOOKUP/INDEX-MATCH).
3. Pivot by first_touch_channel to get conversion count and sum of revenue.

Deliverable: Pivot with channels credited and totals.

Self-check checklist

• [ ] Did you apply a 30-day lookback where relevant?
• [ ] Did each conversion receive exactly one first-touch channel?
• [ ] Are your totals equal to the number of conversions?
• [ ] Did you document how Direct is treated?

Common mistakes and how to self-check

• No lookback window: You credit a touch from months ago. Self-check: filter to a fixed window (e.g., 30 days).
• Counting Direct incorrectly: Either always excluding or always including. Self-check: define a clear rule and apply it consistently.
• Mixing users: Cross-user contamination from shared devices. Self-check: verify user_id consistency and session stitching rules.
• Double-counting conversions: One conversion tied to multiple first touches. Self-check: ensure exactly one earliest touch per conversion.
• Using FCA to evaluate retargeting ROI: FCA under-credits lower funnel. Self-check: pair FCA with last-click or data-driven for bottom-funnel decisions.

Who this is for

• Marketing Analysts seeking to understand discovery channel performance.
• Growth and Performance Marketers running prospecting and awareness campaigns.
• Product Marketers measuring launch and market-entry traction.

Prerequisites

• Basic understanding of channels (Paid Social, Paid Search, Organic, Email, Direct, Referral).
• Comfort with spreadsheets (filters, pivots, basic formulas).
• Familiarity with sessions, users, and timestamps.

Learning path

1. Learn attribution fundamentals and model trade-offs (10–15 min).
2. Apply FCA manually on 3–5 sample journeys (15 min).
3. Build a spreadsheet FCA pipeline with MINIFS and XLOOKUP (20–30 min).
4. Compare FCA results with last-click on the same data (15 min) and note differences.

Practical projects

• Monthly FCA dashboard: channels credited conversions, revenue, and share of revenue.
• Campaign acquisition study: compare FCA vs. last-click for a new awareness campaign.
• Lookback sensitivity analysis: run FCA at 7, 30, and 60 days to see stability of conclusions.

Next steps

• Establish your organization’s lookback and Direct handling policies.
• Automate the spreadsheet process or implement in your BI tool.
• Pair FCA with another model (e.g., last-click) in your monthly reporting.

Mini challenge

You have 1 week of data and 50 purchases. Build a quick FCA summary that shows top 5 first-touch channels by conversions and revenue. Add a note on how results change if Direct is excluded as a channel. Keep it to one clear chart and 3 bullet insights.