How to Interpret Low SIS for Specific Keywords
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Quick answer
Low search impression share (SIS) for a specific keyword is a sign that your ad is not winning as many eligible impressions as it could for that query. It typically points to a budget cap, ad relevance or targeting mismatch, or a competitive bid position. The right response is to check which of those factors is limiting that keyword, then adjust targeting, bids, or negative keywords rather than applying the same change across the whole campaign.
A single keyword with low SIS is not a verdict; it is a diagnostic prompt. Because lost impressions can come from different causes, the most useful next step is to isolate whether the keyword is being throttled by spend, filtered by relevance, or outbid in too many auctions.
What low SIS usually means at keyword level
For a specific search term, low SIS tends to cluster around three issues: the campaign budget runs out before that keyword can win more impressions; Amazon sees the ad as only partly relevant for the query; or your bid and placement are not competitive enough to win a meaningful share of auctions.
- Budget exhaustion: Does the campaign hit its daily limit and stop serving before the search term can gain traction?
- Relevance gap: Is the keyword broad enough that the ad appears in less-qualified auctions and loses share?
- Bid position: Is the keyword earning impressions but losing to stronger bids at key placements?
For recurring low-SIS terms that are clearly wasteful, a tool like Amazon Negative Keyword Tool by Todoza can help separate terms worth negating from those that need bid or budget changes.
How to investigate before changing bids or negatives
Start by pulling a search term report and filtering to the low-SIS keyword. Compare impressions, clicks, spend, ACoS, and ROAS over a meaningful period rather than a single day.
Then test one variable at a time. If spend is capped, raise the campaign budget for that period and see if impressions recover without a bid change. If relevance is unclear, move the keyword to an exact match ad group or tighten match type before negating it elsewhere.
When keyword-level low SIS matters most
Low SIS deserves a focused review when the keyword has strong commercial intent, has converted before, or sits inside a campaign that is already profitable but losing share during peak shopping hours. In those cases, the fix is usually a budget or bid adjustment.
By contrast, if the keyword is broad and regularly produces clicks without orders, low SIS can be a useful signal to add it as a negative or reduce its priority rather than increase spend.
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Treat low SIS at the keyword level as one diagnostic input inside the wider Amazon Ads visibility review process. Mapping the cause for each low-SIS term before changing budgets or negatives helps protect profitable reach without feeding queries that do not convert.