At a glance
Detects unusual cost-per-click deviations from the 30-day baseline. Fires when CPC moves 2 standard deviations above the trailing average. CPC anomalies usually trace to one of three causes: (a) a competitor entered the auction with aggressive bids, (b) Google’s algorithm shifted bid pressure on your keywords, (c) Quality Score dropped because of landing-page or ad-relevance issues. The card surfaces the anomaly in real-time so the merchant can intervene before a 7-day spend cycle locks in the higher cost.
| What it counts | Detects when current-period (rolling) CPC exceeds 2σ above the 30-day baseline mean. Reported as the current CPC value plus the deviation in standard deviations. |
| Sample basis | Google Ads spend and click data, refreshed near-real-time. |
| Sampling threshold | n/a (full data, not sampled). |
| Bot traffic filter | Google Ads applies invalid-click filtering server-side. |
| Time zone | Account time zone. |
| Time window | RT (real-time / rolling 24h vs 30D baseline) |
| Alert trigger | cpc > baseline + 2σ |
| Sentiment key | gads_cpc_anomaly (LOWER_IS_BETTER for absolute CPC; alert fires on deviation) |
| Roles | owner, marketing |
Calculation
Worked example
A UK-based BC store, CPC anomaly reading on Wednesday 15 May 26.| Metric | Current 24h | 30D baseline | Standard deviation | Status |
|---|---|---|---|---|
| Account-wide CPC | £1.82 | £1.84 | £0.18 | Normal (-0.1σ) |
| Brand campaigns CPC | £0.42 | £0.40 | £0.05 | Normal (+0.4σ) |
| Non-brand search CPC | £2.85 | £1.95 | £0.40 | Alert (+2.3σ) |
| Shopping campaigns CPC | £1.62 | £1.55 | £0.18 | Normal (+0.4σ) |
| Display CPC | £0.34 | £0.31 | £0.06 | Normal (+0.5σ) |
- Non-brand search CPC has jumped from £1.95 to £2.85 in the last 24 hours, a 46% increase. This is far outside normal weekly variance.
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Likely causes (in priority of investigation):
- Competitor entry: a new competitor launched an aggressive paid programme, or an existing competitor dramatically increased bids on shared keywords. Check Google Ads’ Auction Insights report for the affected campaign.
- Quality Score drop: if the merchant’s ad relevance or landing-page experience declined, Google’s bid multiplier rises. Check Quality Score per ad group.
- Algorithm shift: Google occasionally adjusts bid pressure across categories; monitor whether the spike persists across multiple days (algorithm) vs single day (competitor or quality).
- Bid strategy change: did the merchant change Smart Bidding settings or budgets recently?
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The financial impact:
- At previous £1.95 CPC × 200 daily clicks = £390/day spend.
- At new £2.85 CPC × 200 daily clicks = £570/day spend.
- £180/day uplift = £5,400 additional spend over the next 30 days if the anomaly persists.
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Recommended response:
- Hour 1: Review Google Ads’ Auction Insights for the affected campaign. Identify which competitors are bidding more aggressively.
- Hour 2: Check Quality Score for affected ad groups. Has it dropped?
- Day 1: If a competitor entry is the cause, decide: (a) match bids and accept higher CPA, (b) hold bids and accept lower position/volume, (c) shift to different keywords with less competition.
- Day 1-2: If Quality Score is the cause, audit landing pages, ad copy relevance, expected CTR.
- Day 7: Re-measure; if anomaly persists, treat as the new baseline and adjust bid strategy.
Sibling cards merchants should reference together
| Card | Why merchants reach for it |
|---|---|
gads_cpc_spike | More aggressive spike-detection variant. |
gads_cpa | CPA companion; rising CPC drives rising CPA. |
gads_quality_score | Quality Score; major driver of CPC. |
gads_total_spend | Total spend; CPC × clicks. |
gads_roas | Return on ad spend. |
gads_alert_cpc_spike | Alert variant. |
Reconciling against the vendor’s own dashboard
Where to look in Google Ads: Reports → Bidding → CPC by hour; Auction Insights for competitive context. Why our number may differ:| Reason | Direction | What to do |
|---|---|---|
| Real-time vs reported. Google Ads reports lag 1-3 hours; this card uses real-time stream. | Vortex IQ may show signal earlier | n/a; earlier is better. |
| Display vs Search. Default behaviour may include or exclude Display CPC. | Variable | Confirm. |
| Brand vs non-brand split. Manual; not natively flagged in Google Ads. | Variable | Configure per-campaign in Vortex IQ. |
Known limitations / merchant FAQs
Q: CPC spiked 50%, should I pause campaigns? Generally no. Pausing destroys bid history; resuming can take 2-4 weeks to recover performance. Better: investigate the cause, adjust bid caps if competitors are pushing CPC unprofitable, or accept the higher CPC if conversion volume justifies it. Q: Why does CPC vary so much between brand and non-brand? Brand CPC is structurally low because branded queries have high CTR and high Quality Score. Non-brand CPC is auction-driven and reflects category competition. The two should be tracked separately. Q: How do I tell competitor entry from algorithm change? Auction Insights shows competitive overlap. If a new competitor appears with high impression share, that’s the cause. If the spike is broad-based across all queries, it’s likely an algorithm shift. Persistent spike (4+ days) suggests algorithm; sharp 1-2 day spike suggests competitor or seasonal. Q: What’s an acceptable CPC for ecommerce? Highly category-dependent. Branded queries: £0.20-£1.00. Non-brand search: £0.50-£3.50 in B2C; £3-£15 in B2B/SaaS. Set thresholds per campaign in Vortex IQ rather than relying on a generic threshold. Q: Can I disable the anomaly alert? Yes, the alert is configurable per profile. Some merchants prefer aggregate CPA monitoring; others want real-time bid-level alerts. The default is on for accounts above £10K/month spend. Q: How does this card interact with Smart Bidding? Smart Bidding will absorb some CPC volatility (raising bids when conversion likelihood is high, lowering otherwise). An anomaly here may signal that Smart Bidding is responding to a real opportunity (rising CPC = rising conversion likelihood) or to noise (rising CPC without conversion benefit). Cross-referencegads_roas.
Q: Display CPC vs Search CPC, should they be in the same threshold?
No. Display CPC is structurally lower (£0.10-£0.50); Search CPC is higher (£0.50-£5+). Configure separate baselines per channel in Vortex IQ.
Q: We use manual CPC bidding. Is the anomaly still useful?
Yes, manual bidding sees CPC anomalies as competitor pressure (higher CPC at same bid means losing auctions, so spend per click rises). Investigate Auction Insights to see who’s pressing.