The only reliable way to diagnose this is a controlled pause test: turn off PPC on a sample of the keywords in question while holding everything else constant, then measure what actually happens to total clicks, conversions, and competitor ad presence on those queries, rather than assuming a universal rule about organic-paid overlap. There is no fixed percentage that applies across all keywords and industries; the degree to which paid and organic clicks are additive versus substitutive varies by query type, brand strength, and SERP layout, which is exactly why a real test beats a general assumption.
Why this isn’t a settled, universal answer
The intuitive assumption is that if you already rank organically at position 1-3, the paid ad next to (or above) it is redundant spend, since a searcher would have clicked the organic result anyway. The countervailing risk is that removing the ad frees that SERP real estate for a competitor’s ad to occupy, potentially intercepting some share of clicks that would otherwise have gone to your organic result, especially for commercial or transactional queries where paid ads sit visually above organic results and get evaluated first by many searchers.
Google’s own research into this question is the most credible starting point, though it’s dated and limited in scope. Google published incrementality studies (most notably referenced in discussions around 2011-era research into paid and organic search interaction) examining what happens to total clicks when advertisers paused ads on queries where they also ranked organically. The general finding was that incremental value from running both varies significantly by query type and brand context: for some queries, a meaningful share of paid clicks were genuinely incremental (the searcher would not have clicked the organic result instead), while for others the overlap was substantial and pausing ads recovered most of the traffic through the organic listing. This research is old enough, and narrow enough in what it directly measured, that it should be treated as directionally informative rather than as a current, universally applicable statistic. Google has not maintained or republished an updated, comprehensive version of this specific research in recent years.
Because the finding varies by query type and because SERP layouts, ad formats, and competitive density have all changed substantially since that older research, the honest position is that this is a testable, page-specific and keyword-specific question rather than one with a single correct answer that generalizes across every account.
Designing the pause test
Select a sample of keywords currently running PPC where you also hold organic position 1-3, ideally grouped by similar characteristics (branded vs. non-branded, informational vs. transactional intent, similar existing ad spend levels) so you can read results by segment rather than lumping everything together. Pause PPC on that sample while leaving a comparable control group of similar keywords running as-is, so you have something to compare against and can separate the effect of the pause from unrelated demand fluctuations (seasonality, market changes) happening at the same time.
Measure, at minimum: total clicks to your domain on the paused keywords (organic clicks after the pause, compared to combined paid+organic clicks before), total conversions attributable to those keywords, and, critically, whether competitor ads now appear in the ad slots you vacated, which you can check directly by searching the keyword yourself (ideally from a clean/incognito session, matched geographically to your target market) or via a SERP-monitoring tool. If a competitor ad appears where yours used to be, check whether your organic click volume for that keyword actually dropped, held steady, or even changed direction relative to the control group; that comparison is the real signal, not the mere presence of a competitor ad.
Run the test for long enough to smooth out day-to-day and week-to-week noise, typically several weeks depending on your keyword volume, and compare the paused segment’s post-pause organic-only performance against its own pre-pause combined performance and against the untouched control segment’s performance over the same window.
Reading the results
If total clicks and conversions on the paused keywords hold roughly steady (organic absorbing most of what paid was delivering, regardless of whether a competitor’s ad now appears in the vacated slot), that’s a reasonably clean signal that the paid spend was largely redundant for that keyword segment, and reallocating that budget elsewhere is defensible.
If total clicks or conversions drop meaningfully after the pause, relative to the control group, that indicates real incrementality: the ad was capturing clicks or conversions that organic ranking alone was not delivering, whether because of format differences (ad extensions, different messaging, different visual prominence), searcher behavior on that specific query type, or a competitor ad genuinely intercepting some of that traffic once the slot opened up. In that case, the paid spend on those specific keywords is earning its keep and shouldn’t be cut based on organic position alone.
As a hypothetical example: imagine a hypothetical SaaS company, “Site H,” that pauses PPC on a set of branded keywords where it already ranks organically in position 1. Hypothetically, if a competitor’s ad then began appearing in that vacated top slot, and total clicks to Site H on those keywords dropped by a meaningful margin relative to a held-out control group of similar keywords that kept running ads, that combination, competitor presence plus an actual measured click decline, would be the signal that the paid spend was genuinely incremental, not redundant, and the test would argue for restoring the ads rather than cutting them.
Practical implication
Treat organic position 1-3 as a reason to test whether PPC spend is redundant on those keywords, not as proof that it is. The decision should be made keyword-segment by keyword-segment based on actual pause-test results, not as a blanket policy applied across an entire account, because query type, brand strength, and competitive ad presence all meaningfully change the answer. Where budget is genuinely constrained and a full pause test isn’t practical for every keyword, prioritize testing on the highest-spend keywords with strong organic position first, since that’s where the potential savings (or the potential exposure, if the test shows real incrementality) is largest, and let the confirmed results from that subset inform the broader account strategy rather than extrapolating from assumption alone.
