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Aug 14, 2026

Evidence Packet for Every Budget Move

An evidence packet is a timestamped record of performance data, decision rationale, and rollback conditions attached to each budget change. It documents the 7-day and 28-day metrics that justified the move and the threshold at which the change should be reversed.

Why Evidence Packets Matter

Budget moves without documentation create two problems: decision amnesia and undefended spend. Six weeks after increasing a channel's budget, the operator who approved it may not remember why. The new operator reviewing spend sees only the current allocation, not the performance that justified it.

Evidence packets solve this by creating a paper trail. They force clarity at the moment of decision and provide a reference point for future audits. When a channel underperforms, the packet shows whether the original thesis still holds or whether conditions have changed.

The 7-Day Snapshot

The 7-day snapshot captures immediate performance after a budget move. It answers: did the channel respond as expected in the first week?

  • ROAS or CPA at day 7 (or day 3 if testing paid social)
  • Spend velocity - did the budget get deployed as planned?
  • Volume metrics - orders, sessions, or conversions depending on channel
  • Any platform-specific flags - account health, policy warnings, creative fatigue signals

The 28-Day Baseline

The 28-day metric is the decision standard. It smooths out weekly noise and reflects true channel economics. This is the number that determines whether the move was correct.

  • ROAS or blended CPA at 28 days
  • Cumulative spend and revenue
  • Repeat purchase rate or LTV proxy if available
  • Comparison to the channel's historical 28-day performance (if scaling up) or to benchmark (if new channel)

The Decision Metric and Trigger

Every budget move must name the single metric that triggered it. This is not the full business case - it is the one number that crossed a threshold.

Examples: 'Increased Google Shopping budget because 28-day ROAS hit 3.2x (threshold: 3.0x).' Or: 'Reduced TikTok spend because 7-day CPA rose to $18 (rollback trigger: $17).' Naming the metric prevents post-hoc rationalization and makes rollback automatic.

The Rollback Rule

A rollback rule is a pre-set condition that reverses the budget move without debate. It removes emotion from underperformance and forces action on drift.

Set the rollback threshold at the 28-day mark. If the channel does not hit the target metric by day 28, revert the budget and document why it failed. Common rollback rules:

  • ROAS falls below X for 28 days - reduce budget by Y%
  • CPA rises above X for 28 days - pause channel entirely
  • Spend velocity is below 80% of plan - reduce daily budget and investigate
  • Creative fatigue detected (CTR down >15% week-over-week) - pause and refresh creatives before re-testing

The Evidence Packet Template

Document each move in a single record. This can live in a spreadsheet, Slack thread, or ops tool - the format matters less than consistency.

  • Date of move
  • Channel and campaign
  • Old budget vs. new budget (dollar amount and % change)
  • Decision metric and threshold that triggered the move
  • 7-day performance snapshot (date captured, ROAS/CPA, spend, volume)
  • 28-day performance snapshot (date captured, ROAS/CPA, spend, volume, repeat rate if tracked)
  • Rollback rule (the condition that reverses this move)
  • Owner name
  • Status: Active, Rolled Back, or Graduated (moved to permanent allocation)

Execution Checklist

Before approving any budget change, verify:

  • The decision metric is named and the threshold is written down
  • 7-day and 28-day baselines are captured at the time of the move (or within 24 hours)
  • The rollback rule is specific enough that a different operator can execute it without interpretation
  • The packet is stored in a shared location and linked to the budget change in the ad platform or finance tool
  • A calendar reminder is set for day 28 to review the 28-day metric and decide: hold, scale, or rollback

Questions

FAQ

What if a channel is new and has no historical baseline?

Use the benchmark from similar channels or competitors. If scaling Google Shopping from $500/day to $2000/day, the baseline is the current 28-day ROAS at $500/day. If launching a new channel like Pinterest, set the rollback threshold at the blended brand ROAS minus 20% (e.g., if brand ROAS is 2.5x, rollback if Pinterest hits below 2.0x by day 28).

Should the 7-day snapshot trigger rollback decisions?

No. The 7-day snapshot is diagnostic only. It flags problems early (e.g., a platform outage, creative underperformance) but does not trigger rollback. Rollback decisions are made at 28 days. Use 7-day data to decide whether to pause and investigate before day 28 completes.

How often should budget moves be documented?

Every move, including small daily adjustments. If the budget for a campaign changes by more than 10% or the daily spend moves by more than $100, document it. Micro-adjustments below that threshold can be logged in batch weekly.

What happens if the rollback rule is met but business context has changed?

Execute the rollback as planned. Document the reason for the underperformance in a separate note (e.g., 'Rolled back due to iOS update impact on pixel tracking'). Then run a new test with updated assumptions and create a new evidence packet. Overriding rollback rules erodes the system.

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