Click-Through Rate (CTR)

What is Click-Through Rate (CTR)?

Click-Through Rate (CTR) is the share of impressions that result in a click. It is calculated as (clicks ÷ impressions) × 100%. In performance reporting, CTR may be computed on served impressions or restricted to viewable impressions (“viewable CTR”), depending on the policy adopted.

Why is Click-Through Rate (CTR) important?

CTR is a leading indicator of message–market fit and the effectiveness of creative and targeting. In auction-based ad platforms, sustained improvements in CTR feed into expected CTR/quality signals, which can improve ad position and reduce effective costs at a given bid. Operationally, CTR helps teams distinguish top‑of‑funnel problems (weak creative or targeting) from post‑click frictions (slow pages, poor offers), enabling faster, more targeted optimization.

How does Click-Through Rate (CTR) work?

1. A platform records an impression when an ad or listing is served (and, optionally, when it meets a defined viewability threshold).
2. A click is registered when the user activates the ad or link; platforms separately report total and unique clicks.
3. CTR is computed over a defined scope (campaign, ad group, creative, placement, audience, keyword, or time window). Some teams standardise on viewable impressions and apply invalid traffic (IVT) filtration to ensure CTR reflects human intent.
   

What is Click-Through Rate (CTR) used for?

• Channel diagnostics. Identify whether underperformance stems from targeting/creative (low CTR) versus conversion-path issues (normal CTR, low CVR).
• Auction efficiency. Improve quality signals and Ad Rank via higher expected CTR to win better positions at lower costs.
• Creative governance. Benchmark messages, formats, and placements across geographies, brands, and affiliates.
• Lifecycle messaging. In email, track unique CTR (unique link clicks ÷ delivered emails) and separate it from click‑to‑open rate (CTOR).
  

Examples of Click-Through Rate (CTR) usage

• Paid search (sportsbook): 310 clicks from 12,400 impressions on “UEFA odds” → 2.5% CTR. Tightening ad–keyword relevance and extensions often raises CTR and improves position at similar CPC.
• Meta prospecting (casino): Distinguish CTR (all) from CTR (link). Optimise for link CTR when the goal is website traffic or post‑click conversion.
• Email (bonus reactivation): 2,000 unique link clicks on 100,000 delivered emails → 2.0% unique CTR. With 25,000 opens, CTOR = 8.0%. Use both metrics to evaluate subject line (opens) vs creative/offer (clicks).
• Display (affiliate inventory): Apply IVT filtration and, where possible, compute CTR on viewable impressions to reduce bias from non‑viewable placements and bots.

Benefits of using Click-Through Rate (CTR)

• Fast feedback loop. CTR responds quickly to creative and targeting changes, enabling high‑velocity A/B testing.
• Quality and cost leverage. Higher expected CTR can strengthen auction quality signals, improving delivery and reducing effective CPC at the same bid.
• Comparability. With documented counting rules (served vs viewable, total vs unique clicks), CTR becomes a reliable benchmark across brands, geographies, and placements.

Tips for using Click-Through Rate (CTR)

1. Define the metric precisely. Specify whether you use total or unique clicks, the impression base (served vs viewable), attribution windows, and de‑duplication rules.
2. Filter invalid traffic. Apply IVT controls (e.g., data‑centre IP lists, JavaScript integrity checks, anomaly detection) before computing CTR.
3. Segment aggressively. Break out CTR by country, device, surface (feed/stories), audience, branded vs generic queries, and frequency to reveal actionable deltas.
4. Pair CTR with downstream metrics. Review CVR, CPA, LTV/quality alongside CTR to avoid optimising for low‑value clicks (e.g., bonus seekers).
5. Use CTR to guide auctions—not as the goal. Focus on ad–landing page relevance to strengthen quality signals rather than chasing vanity CTR.
6. For email, separate metrics. Track unique CTR on delivered and CTOR on opens; optimize creative/layout for CTR and subject lines/sender for opens.
7. Document experiment context. When A/B testing, log audience size, frequency caps, creative differences, dates, and any concurrent promotions to interpret CTR shifts correctly.