Video Action Campaign Missing Target CPA After Budget Increase
Northwind Solar runs a Video action campaign with a $40 Target CPA and a $500 daily budget. Before a recent change, it averaged 55 conversions per week at a $47 CPA, spent about $2,600 per week, and lost 28% of impression share to rank. The team raised the daily budget to $800 to reach a goal of 80 conversions per week. Two weeks later, conversions are 62 per week, CPA is $58, spend is about $3,600 per week, and lost impression share to rank is 31%. The conversion lag is seven days, so the most recent week is incomplete. The sales team reports no change in lead quality. The campaign uses Target CPA bidding, and the account also runs Search with a separate budget. The team wants to know whether to keep the higher budget, lower the target CPA, or change bid strategy. It cannot exceed a $65 blended CPA.
1. Diagnose why CPA rose after the budget increase. Which factors are most likely and which are not supported by the setup?
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The budget increase was not the right lever because the campaign was limited by rank, not budget. It was already spending only about $2,600 of a $500 daily budget, and after the change it spends about $3,600 per week, still below $800 per day. Lost impression share to rank rose to 31%, which points to bids and auction competitiveness rather than a budget cap. Raising the budget cannot fix a rank constraint.
The CPA rise is most likely explained by a combination of incomplete conversion lag, seasonal auction pressure, and the campaign reaching less efficient inventory as spend rose. The most recent week is incomplete, so its conversions are understated and its CPA is overstated. Lead quality is unchanged, which argues against the campaign suddenly reaching bad audiences. Creative fatigue is not supported because no creative metrics are given. A bidding error is possible because the $40 target is far below the actual $47 and $58 CPAs; an unrealistically low target can restrict delivery and then produce unstable results when spend changes.
2. What bid and budget actions should Northwind take over the next 14 days to reach 80 conversions per week without exceeding a $65 blended CPA?
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Do not lower the target CPA; that would tighten delivery when the campaign is already losing impression share to rank. Keep the daily budget at $800 for now because it is not the binding constraint, but do not treat it as a reason to spend more. Raise the Target CPA gradually, for example from $40 to $50 and then toward $60 if volume responds, while watching the blended CPA across Search and Video. At $58 CPA and 62 conversions, Video is already near the ceiling; reaching 80 conversions at $60 would cost about $4,800 per week, or roughly $686 per day, which the current budget can support.
Make one change at a time and allow at least a week plus the seven-day conversion lag before judging. If raising the target CPA increases volume but pushes blended CPA toward $65, stop and shift budget back to Search. Use a portfolio bid strategy only if Search and Video share a conversion goal and the team can manage a combined target; otherwise keep them separate so Video does not distort Search. Review lost impression share to rank after the bid change to confirm the constraint is easing.
3. How should Northwind monitor the change and decide whether to keep the higher budget?
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Build a weekly cohort view that waits for the seven-day lag before comparing CPA and conversion volume. Track spend, conversions, CPA, lost impression share to rank, and lost impression share to budget in the same report. If spend remains below the daily budget and rank is still the constraint, the budget is not the problem and should not be increased again. If rank improves but budget becomes the constraint, then the higher budget is doing useful work.
Set a decision rule: keep the $800 budget only if Video CPA stays at or below $60 after lag and blended CPA stays under $65; otherwise return to $500 and fix targeting or creative first. Check lead quality weekly with sales because a cheap lead that does not qualify is worse than a slightly more expensive qualified lead. Do not judge the two-week result as final while the latest week is incomplete. The key judgment is that budget increases amplify a working bid strategy; they do not repair a rank-constrained one.