Lin-Rodnitzky Ratio Monitor
Tracks the Lin-Rodnitzky ratio — cost per conversion of all search queries divided by cost per conversion of converting queries only — and charts it over time in a Google Sheet.
by Nils Rooijmans·nilsrooijmans.com/google-ads-script-lin-rodnitzky-ratio
Overview
The Lin-Rodnitzky ratio is a one-number health check for Search accounts: total cost/conversion divided by cost/conversion of queries that converted at least once. 1.0-1.5 = too conservative, 1.5-2.0 = well managed, 2.0-2.5 = too aggressive, above 2.5 = money is burning on queries that never convert. This script computes the ratio daily over a rolling window and appends it to a template Google Sheet that graphs the trend.
Setup
- 1Make a copy of the template sheet linked in the script header (docs.google.com/spreadsheets/.../copy).
- 2Add the copied sheet's URL to SPREADSHEET_URL.
- 3Open your Google Ads account and go to Tools → Bulk Actions → Scripts.
- 4Click the + button to create a new script and paste the code below.
- 5Authorize, preview (the first run backfills INITIAL_PERIOD days), then schedule daily — the author prefers 6AM.
Configuration Variables
| Variable | Default |
|---|---|
SPREADSHEET_URL | (required) |
INITIAL_PERIOD | 180 |
LOOKBACK_WINDOW | 28 |
Expected Output
One row per day in the 'LR Ratio' sheet: date, cost/conv (all queries), cost/conv (converting queries), Lin-Rodnitzky ratio — with the template's chart showing the trend.
Notes
Popularized by Will Lin and David Rodnitzky; interpret the bands as a conversation starter, not gospel — accounts deliberately investing in growth run higher ratios. Requires conversion tracking with search query data.