I love a good hierarchy / process workflow for uncovering the core cause of ad performance swings, so this tweet on Google Ads is for me.

We divide Google Ads metrics into 4 levels:

Level 1: CPA, ROAS, Conversions
Level 2: CTR, CR, Clicks, Impressions, CPC
Level 3: Impression share, Quality score, Ad relevance, Landing page experience
Level 4: Keyword, ad copy, device, audience segment, geographic.

ID which level 1 metric is the problem and work down the list of related metrics in 2-4 to determine what you need to change.

In most cases, potential issues fall into 3 main areas:

1. Account - ads, ad relevance, landing page.
2. Market - competition, keywords, location.
3. Website - user experience, mobile optimizations

For bonus points, set up automated alerts to react faster to performance drops.