Target Impression Share is an automated Google Ads bidding strategy designed to achieve a chosen level of visibility in Search results. The advertiser selects where adverts should appear, the percentage of eligible impressions they want to target and the maximum CPC bid limit. Google then manages bids towards that visibility objective.
It is most commonly associated with brand campaigns. An advertiser may want an advert to appear whenever someone searches for its company name, particularly when competitors, marketplaces, affiliates or comparison websites are also bidding on those searches.
However, Target Impression Share can be expensive when used without restraint. A campaign can achieve greater visibility while generating fewer conversions, a higher CPA or less profit. Requesting 100% Absolute Top Impression Share effectively tells Google that being the first advert is strategically important—even when the next click is commercially unaffordable.
Visibility is therefore the objective, not proof of success.
This guide explains how Target Impression Share works, what Anywhere, Top and Absolute Top mean, how to choose a target and maximum CPC limit, when the strategy is useful and how it compares with the other principal Google Ads bidding strategies.
What Is Target Impression Share Bidding?
Target Impression Share automatically sets bids to help an advert achieve a selected share of eligible Google Search impressions in a chosen location.
The advertiser configures three principal controls:
Placement: Anywhere, Top or Absolute Top.
Target Impression Share: the percentage of eligible impressions the strategy should try to capture in that placement.
Maximum CPC bid limit: the highest bid the strategy is normally allowed to set.
For example, an advertiser could ask Google Ads to target 80% Search Top Impression Share with a maximum CPC bid limit of £4.
Google would then manage bids towards showing the adverts among top ads for approximately 80% of the impressions they were eligible to receive, subject to auction conditions, targeting, budget, Ad Rank and the CPC limit.
The percentage is a target rather than a guarantee. A campaign may miss it when the budget is too low, the CPC limit is too restrictive, advert quality is poor, targeting limits eligibility or competition changes.
Google’s current Target Impression Share guidance confirms that it can be used as a standard strategy for one campaign or a portfolio strategy across several eligible campaigns.
Target Impression Share Is Available for Search Campaigns
Target Impression Share is designed for the Google Search Network. It is not a general awareness strategy for Display, Demand Gen, YouTube or Performance Max.
Google also states that the impression-share calculation excludes Search Partners. This is important when interpreting reports: the target and resulting impression-share data relate to eligible Google Search auctions rather than every impression across the wider Search Network.
If Search Partners are enabled, assess their performance separately. Do not assume a Google Search impression-share target describes coverage on partner sites.
Is Target Impression Share Smart Bidding?
Target Impression Share is automated bidding, but it is not normally classified as conversion-based Smart Bidding.
Google’s Smart Bidding family includes:
Maximise Conversions;
Maximise Conversions with a Target CPA;
Maximise Conversion Value;
Maximise Conversion Value with a Target ROAS.
Those strategies optimise for conversions or conversion value using auction-time bidding. Google’s current Smart Bidding guide distinguishes Target Impression Share and Maximise Clicks as automated strategies that do not include auction-time bidding.
Target Impression Share instead manages bids towards a visibility objective. It does not ask which eligible search is most likely to generate a Qualified Lead, customer, order or profit.
This distinction prevents a common misunderstanding: automated bidding does not always mean conversion optimisation.
The Three Placement Options Explained
Target Impression Share offers three placement goals. The correct choice depends on how prominently the advert genuinely needs to appear.
Anywhere on the Results Page
The strategy attempts to show the advert anywhere among Search results for the selected percentage of eligible impressions.
This is the broadest and normally least aggressive location objective. It may be suitable when visibility matters but the business does not need to appear among top ads consistently.
An Anywhere target does not guarantee a top position. It asks the strategy to obtain an impression somewhere in the eligible Search results.
Top of the Results Page
The strategy attempts to show the advert among top ads for the selected share of eligible top impressions.
Top ads are adjacent to the top organic search results. Google notes that they are generally above the organic results, although top ads can appear below them in some circumstances because Search page layouts are dynamic.
Top does not mean first advert. It means the advert appeared among the group of top ads.
This option often provides a more balanced visibility objective for brand campaigns than demanding Absolute Top coverage.
Absolute Top of the Results Page
The strategy attempts to show the advert as the first advert among top ads for the selected share of eligible absolute-top impressions.
Absolute Top is the most aggressive placement goal. It can maximise prominence, but it can also raise CPCs substantially when competitors are bidding on the same searches.
The first paid position is not automatically the most profitable position. Advertisers should use Absolute Top only when the incremental value of being the first advert justifies the additional cost.
Impression Share Is Based on Eligibility
Impression Share is not the percentage of every search conducted for your entire market. It is the impressions received divided by the estimated impressions the advert was eligible to receive.
Eligibility depends on factors including:
keyword targeting and match types;
location and language settings;
negative keywords;
advert approval and policy status;
campaign schedule;
budget;
Ad Rank and auction thresholds;
the search context and available inventory.
Suppose a brand campaign receives 800 impressions and Google estimates that it was eligible for 1,000. Its Search Impression Share is 80%:
800 ÷ 1,000 × 100 = 80%
This does not mean only 1,000 brand searches occurred. Some searches may not have matched the campaign, may have fallen outside the targeted locations or schedule, or may have been ineligible for other reasons.
Impression Share, Top Rate and Absolute Top Rate Are Different
Google Ads includes several visibility metrics that sound similar but answer different questions.
Search Impression Share
The percentage of eligible Search impressions the campaign received.
Search Impression Share = Impressions received ÷ Estimated eligible impressions
Search Top Impression Share
The impressions received among top ads divided by the estimated number of top impressions the campaign was eligible to receive.
Search Absolute Top Impression Share
The impressions received as the first advert among top ads divided by the estimated number of absolute-top impressions the campaign was eligible to receive.
Search Top Impression Rate
The percentage of the campaign’s actual impressions that appeared among top ads.
Search Absolute Top Impression Rate
The percentage of actual impressions that appeared as the first ad among top ads.
Share measures captured opportunity against estimated eligibility. Rate measures the placement of impressions that actually occurred.
A campaign could have a high Absolute Top Rate but low Absolute Top Impression Share if most of its limited impressions appear first while it misses many other eligible auctions.
Our Google Search Impression Share guide explains these metrics, including Search Lost IS due to budget and rank, in more detail.
How the Target Percentage Works
The Target Impression Share setting tells Google the proportion of eligible impressions the strategy should try to achieve in the selected placement.
For example:
80% Anywhere asks Google to pursue an impression somewhere in the results for 80% of eligible opportunities.
80% Top asks Google to pursue a place among top ads for 80% of eligible top opportunities.
80% Absolute Top asks Google to pursue the first ad position for 80% of eligible absolute-top opportunities.
These are materially different requests. The same percentage can create very different CPCs and spend according to the placement option.
Should You Target 100% Impression Share?
Rarely by default.
A 100% target asks the strategy to compete for the most difficult marginal auctions as well as the easier ones. Those final percentage points may be disproportionately expensive because they include searches where:
competitors bid aggressively;
advert relevance is weaker;
the query is a loose match;
the user is outside the strongest location;
the search is unlikely to convert;
the auction requires a much higher Ad Rank.
Even Google’s example of 100% brand visibility describes what the strategy attempts to do, not a universal best practice.
For many campaigns, a target below 100% provides a better balance between presence and cost. There is no universally correct percentage. Test the incremental cost, clicks, conversions and business value gained as the target increases.
How the Maximum CPC Bid Limit Works
The maximum CPC bid limit restricts the bids Target Impression Share can set.
This is an essential control. A high target combined with Absolute Top placement can encourage aggressive bids. Without a commercially reasoned limit, the campaign may pay substantially more to protect visibility.
However, setting the limit too low can prevent the strategy from reaching the target. Google may report that bid limits are constraining the strategy, while Search Lost IS (rank) remains high.
The limit is therefore a trade-off:
Higher limit: more freedom to reach difficult auctions, but greater CPC exposure.
Lower limit: stronger cost protection, but a higher probability of missing the visibility goal.
Do not raise the limit simply because the strategy has missed its target. First determine whether the additional visibility is commercially worth purchasing.
How to Calculate a Defensible CPC Limit
Even when the objective is visibility, the maximum CPC should be connected with business economics.
For lead generation:
Maximum affordable CPC = Target CPA × Expected conversion rate
If the target cost per lead is £100 and the landing page converts 5% of clicks:
£100 × 0.05 = £5
At a £5 average CPC and 5% conversion rate, the expected CPA is £100 before allowing for variation.
For a more commercial calculation:
Maximum affordable CPC = Allowable customer acquisition cost × Click-to-lead rate × Lead-to-sale rate
If the business can spend £1,000 to acquire a customer, 5% of clicks become leads and 10% of leads become customers:
£1,000 × 0.05 × 0.10 = £5
The bid limit does not need to equal this theoretical ceiling. A prudent limit may be lower, especially while the campaign’s search terms and conversion rate remain uncertain.
Brand economics also require an incrementality adjustment. Some people clicking a brand advert would otherwise have used the organic result. The value of a paid brand click is therefore not necessarily equal to the value of a completely new customer acquired through a generic search.
When Target Impression Share Can Be a Good Choice
Target Impression Share is appropriate when visibility itself has a clear strategic value.
Brand Defence
Competitors may bid on a company name, while affiliates, resellers, comparison sites or marketplaces can also appear prominently. Target Impression Share can help maintain paid visibility on high-priority brand searches.
This use case is strongest when:
competitors are actively appearing;
brand searchers may be diverted;
messaging or offers need to be controlled;
organic results do not fully protect the journey;
the brand campaign has a defined visibility requirement.
It does not follow that every brand campaign needs 100% Absolute Top coverage. Manual CPC bidding often provides sufficient control at a lower cost, especially where competition is limited.
Our guide to bidding on your own brand terms covers incrementality, competitor defence and organic overlap in more detail.
High-Priority Strategic Searches
Some organisations need a strong presence for a small, tightly defined group of commercially or reputationally important searches.
Examples could include:
a flagship service launch;
a critical local market;
an event with a fixed promotional window;
a small set of regulated or high-consideration terms;
a brand or product recall search where controlled messaging is important.
Keep the targeting narrow. Applying a visibility target across a large generic keyword set can make the strategy expensive and commercially unfocused.
Local Visibility
A local business may want to appear prominently for selected searches in a tightly bounded service area. Target Impression Share can support this when local presence is the explicit goal and the campaign separates the most important keywords.
Local advertisers should still evaluate calls, appointments and sales. Visibility without serviceable enquiries is not useful.
Awareness in Search Results
Target Impression Share can create repeated presence for searches closely associated with a category. This is a form of Search visibility rather than broad-reach brand advertising.
It works only where relevant searches occur. It does not provide the visual reach, frequency controls or audience breadth of Display, Demand Gen or YouTube.
When Target Impression Share Is Usually the Wrong Strategy
Target Impression Share is normally a poor fit when the real objective is leads, sales, revenue or profit, and those outcomes can be measured reliably.
Avoid using it as the default when:
the campaign has strong conversion tracking and sufficient volume;
budgets are limited, and every click needs commercial justification;
keyword intent varies substantially;
the campaign includes broad generic discovery terms;
the advertiser is trying to reduce CPA;
transaction or lead values differ;
the target is motivated mainly by wanting to appear above a competitor;
100% coverage has no evidenced incremental value.
Visibility strategies can win a positional contest while losing the commercial one.
Should You Use Target Impression Share for Brand Campaigns?
Sometimes—but not automatically.
Brand campaigns are the strongest potential use case because visibility can defend an existing relationship and control messaging. However, brand traffic is usually highly relevant and may already have strong organic coverage.
Consider four questions:
Are competitors or intermediaries actually appearing on the searches?
What happens when the paid brand advert is absent?
Does greater paid prominence create incremental conversions or merely move organic clicks into paid reporting?
How much does the final percentage of visibility cost?
Manual CPC is often our preferred starting point for brand because it allows explicit control over bids and cost. Target Impression Share becomes more compelling when there is a genuine, measurable need to maintain a defined level of visibility.
If used, begin with a defensible target and CPC limit rather than 100% Absolute Top by habit. Monitor Auction Insights, organic presence, conversion performance and incremental value.
Target Impression Share for Competitor Keywords
Using the strategy on competitor-brand keywords can be expensive. Competitor searches often give the named business a major relevance advantage, while the challenger may experience lower CTR, weaker Quality Score and poorer conversion rates.
Target Impression Share can respond by bidding more aggressively to pursue visibility. This may increase CPC without making the offer more relevant.
If competitor bidding is strategically justified:
isolate it in a separate campaign;
use a strict CPC limit and budget;
avoid misleading advert copy;
send traffic to a genuinely comparative or relevant landing page;
measure customers and revenue rather than impressions;
stop if the economics do not work.
Target Impression Share does not allow you to guarantee that you will outrank one named competitor in every auction. It pursues your selected share and placement objective within the auction system.
Target Impression Share and Keyword Match Types
The strategy manages bids, but keyword targeting determines which searches can enter the campaign.
Using Broad Match with an aggressive visibility target can expand the campaign into searches that are only loosely related to the intended visibility objective. Google may then pursue prominence for queries the advertiser did not originally imagine.
For brand defence and other tightly defined visibility campaigns, Exact and Phrase Match normally provide a clearer starting structure. Add negative keywords and review search terms regularly.
Our guide to Google Ads keyword match types explains how modern Exact, Phrase and Broad Match interpret searches.
Do Bid Adjustments Work with Target Impression Share?
Target Impression Share does not use existing positive and negative bid adjustments. Google manages bids towards the selected visibility target.
The main exception is a −100% device bid adjustment, which can prevent adverts from showing on a selected device type.
This means an existing +30% mobile adjustment, −20% location adjustment or schedule bid modifier should not be expected to steer Target Impression Share bids.
Campaign targeting and exclusions still matter. An advert schedule can restrict the days and times when adverts are eligible, and location targeting can define where the campaign operates. The difference is that percentage bid modifiers don’t control the strategy’s bids.
Review these settings before switching from Manual CPC or Maximise Clicks. A campaign previously dependent on bid adjustments may behave differently under Target Impression Share.
How to Set Up Target Impression Share
Google changes the interface regularly, so labels may move. The strategic sequence remains consistent.
For a New Search Campaign
Create a campaign and select the appropriate objective or create it without goal guidance where available.
Choose the Search campaign type.
Configure conversion goals, networks, locations, languages and audiences.
Open the bidding section.
If Google recommends another strategy, choose the option to select a bid strategy directly.
Select Target Impression Share.
Choose Anywhere, Top or Absolute Top.
Enter the desired Target Impression Share percentage.
Enter a maximum CPC bid limit.
Complete the budget, keyword, advert, asset and landing-page setup.
Review all settings before publishing.
For an Existing Campaign
Open the campaign.
Select Settings.
Open Bidding.
Choose Change bid strategy or the equivalent editing option.
Select Target Impression Share.
Choose the placement goal.
Set the target percentage.
Set the maximum CPC bid limit.
Save the change.
Record the date and configuration. Avoid changing match types, adverts, budget and landing pages simultaneously unless necessary; too many changes make the result difficult to diagnose.
As a Portfolio Strategy
Target Impression Share can also be created as a portfolio strategy across multiple eligible Search campaigns.
Group campaigns only when they share a compatible visibility objective. A brand-defence campaign and a broad generic prospecting campaign rarely need the same strategy, target and CPC constraints.
How to Choose Anywhere, Top or Absolute Top
Use the least aggressive placement that can meet the strategic need.
Choose Anywhere When
presence matters more than prominence;
the market has relatively little advertising competition;
budget efficiency matters;
the campaign is testing whether paid coverage adds value.
Choose Top When
visibility among top ads is strategically important;
the campaign needs a stronger presence without always demanding first-ad position;
brand or high-priority searches face meaningful competition;
the business can justify the expected CPC.
Choose Absolute Top When
being the first advert has a specific evidenced value;
the keyword set is extremely focused;
the budget and CPC limit can support the objective;
conversion and incrementality data justify the premium.
Absolute Top should be a deliberate commercial choice, not a vanity metric.
How to Optimise a Target Impression Share Campaign
Automated visibility bidding still requires active management.
Compare the Target with Achieved Impression Share
If achieved share is below target, investigate:
Search Lost IS (rank);
Search Lost IS (budget);
the maximum CPC limit;
ad relevance and landing-page experience;
keyword eligibility and search volume;
policy or approval restrictions.
Do not assume the CPC limit is always the problem. Raising it can increase cost without solving weak ad relevance or a restricted budget.
Review Search Terms
The strategy may be achieving visibility for the wrong searches. Inspect the search terms report, add negative keywords and separate different intents.
High impression share is not desirable when the eligible query set contains irrelevant or low-value searches.
Monitor CPC Inflation
Compare average CPC before and after adopting the strategy. Segment brand, generic and competitor traffic.
If CPC rises materially, calculate what the additional spend purchased:
greater Search Impression Share;
higher Top or Absolute Top coverage;
more clicks;
additional conversions;
incremental customers or revenue.
If the campaign gains visibility but no commercial benefit, reduce the target, change the placement, lower the limit or test another strategy.
Review Auction Insights
Auction Insights can show which advertisers overlap with your campaign and how often they appear above it. Use the report to understand competition, not to create an emotional bidding contest.
An aggressive competitor can make the final percentage of share extremely expensive. Your bidding ceiling should still be determined by business value.
Separate Keyword Types
Keep brand, generic and competitor terms in different campaigns. Their relevance, CPCs, conversion rates and reasons for visibility differ.
A single Target Impression Share setting across all three prevents sensible control and produces misleading averages.
Measure Conversions and Incrementality
Target Impression Share does not use conversions as its primary bidding objective, but Google Ads conversion tracking remains essential for evaluation.
For lead generation, connect adverts with qualified leads, opportunities, sales and revenue through offline conversion tracking.
Brand advertisers should also consider incrementality experiments where feasible. A paid conversion is not necessarily an incremental conversion if the same person would otherwise have clicked the organic listing.
Target Impression Share vs Manual CPC
Both strategies provide a way to control Search visibility, but the bid-setting responsibility differs.
Manual CPC
The advertiser sets keyword and ad-group bids. It provides granular cost control but requires ongoing management.
Manual CPC is often preferable when:
brand CPCs are stable;
individual keywords have known values;
the advertiser wants direct limits rather than a visibility target;
a modest impression-share range is sufficient;
controlling cost is more important than hitting a precise coverage goal.
Target Impression Share
Google manages bids towards a selected visibility percentage and placement.
It is often preferable when:
a defined coverage goal matters;
maintaining Top or Absolute Top presence has evidenced strategic value;
managing bids manually would be inefficient;
the CPC limit can contain financial exposure.
For many brand campaigns, we prefer to begin with Manual CPC and move to Target Impression Share only when the account needs a specific visibility outcome that manual bidding is not achieving efficiently.
Target Impression Share vs Maximise Clicks
Maximise Clicks bidding attempts to generate the greatest number of clicks within budget. Target Impression Share attempts to achieve visibility in a chosen Search position.
Maximise Clicks is appropriate when traffic volume is the immediate objective. Target Impression Share is appropriate when coverage or prominence is the immediate objective.
Neither strategy directly optimises for conversions or value. Target Impression Share may accept higher CPCs to achieve position, while Maximise Clicks has an incentive to find a larger volume of affordable traffic.
Target Impression Share vs Maximise Conversions and Target CPA
Maximise Conversions and Target CPA optimise towards the number of selected conversion actions rather than Search visibility.
They are generally more appropriate when:
lead or sales volume is the objective;
conversion tracking is accurate;
enough relevant conversion evidence exists;
visibility has no independent strategic value.
A conversion strategy may deliberately accept lower impression share if the missed auctions appear unlikely to convert profitably. That can be commercially correct even when a competitor appears more often.
Target Impression Share vs Maximise Conversion Value and Target ROAS
Maximise Conversion Value and Target ROAS optimise towards recorded value and return.
They are stronger candidates when order values vary, margins matter or lead-generation CRM stages, and revenue are available.
Target Impression Share asks whether the advert appeared in the desired place. Value-based bidding asks whether the campaign generated valuable outcomes. Where value can be measured accurately, the latter is usually closer to the commercial goal.
Common Target Impression Share Mistakes
Targeting 100% Absolute Top by Default
The final impressions can be disproportionately expensive. Begin with a defensible objective and test whether higher prominence creates incremental value.
Setting an Unlimited or Excessive CPC Limit
A high target and permissive limit can create severe CPC inflation. Ground the limit in conversion rate, customer value and margin.
Setting the CPC Limit Too Low
The strategy cannot reach the target when it is prevented from entering competitive auctions. If the required CPC is unaffordable, lower the visibility target rather than assuming the business must pay more.
Using the Strategy for Generic Lead Generation
High placement does not guarantee qualified leads. Use conversion or value-based bidding when meaningful outcomes can be measured at sufficient volume.
Mixing Brand and Non-Brand Keywords
Different keyword types need different budgets, targets and economic expectations. Separate them.
Ignoring Search-Term Quality
The system can achieve high visibility across an unsuitable query set. Review search terms and negatives.
Confusing Impression Share with Impression Rate
Share compares impressions with estimated eligibility. Rate describes where actual impressions appeared. Use the correct metric for the question.
Expecting Bid Adjustments to Work
Existing modifiers are ignored, apart from −100% device exclusions. Use targeting, campaign separation and the strategy’s core settings instead.
Treating Competitor Position as the Business Goal
Outranking another advertiser can become expensive without creating customers. Profitability should define the ceiling.
A Practical One PPC View on Target Impression Share
Target Impression Share is a specialist visibility strategy rather than a default bidding method for performance advertising.
Its clearest use is a tightly controlled brand or strategic-keyword campaign where the business has a genuine reason to maintain presence. Even then, 100% Absolute Top should not be assumed to be optimal.
Our preferred hierarchy is:
define why visibility has independent value;
isolate the relevant keywords in their own campaign;
use Exact and Phrase Match with strong negatives;
calculate a commercially affordable CPC limit;
choose the least aggressive placement that meets the need;
begin with a measured target rather than automatically selecting 100%;
monitor lost share, CPC, conversions and incrementality;
compare the result with Manual CPC or conversion bidding.
For brand campaigns without material competitor pressure, Manual CPC may produce sufficient coverage with better cost control. For direct-response campaigns with trustworthy conversion data, Target CPA or Target ROAS will usually align more closely with the business objective.
The purpose of paid search is not to win every auction. It is to win the auctions that create enough commercial value to justify their cost.
Frequently Asked Questions About Target Impression Share
What Does Target Impression Share Do?
It automatically manages bids to help an eligible Search campaign achieve a selected percentage of impressions in an Anywhere, Top or Absolute Top placement.
Is Target Impression Share Available for Performance Max?
No. It is a Search bidding strategy. Performance Max uses conversion or conversion-value bidding.
Is Target Impression Share Smart Bidding?
It is automated bidding, but Google distinguishes it from conversion-based Smart Bidding and states that it does not include auction-time bidding.
What Is the Difference Between Top and Absolute Top?
Top means the advert appears among top ads. Absolute Top means it is the first advert among top ads.
Does Top Always Mean Above Organic Results?
No. Google states that top ads are generally above the top organic results, but they may appear below them in some Search layouts.
Does a 100% Target Guarantee 100% Impression Share?
No. Budget, CPC limits, Ad Rank, eligibility, competition and other auction conditions can prevent the campaign from achieving the target.
What Maximum CPC Limit Should I Use?
Use a limit supported by conversion rate, customer value, margin and historic market CPCs. A limit that is too low restricts visibility, while one that is too high exposes the campaign to expensive clicks.
Do Bid Adjustments Work?
Existing bid modifiers are generally ignored. A −100% device adjustment can still exclude a device type.
Is Target Impression Share Good for Brand Campaigns?
It can be useful when competitors or intermediaries threaten brand visibility. Manual CPC may be more economical when competition is limited or a precise visibility target is unnecessary.
Is Target Impression Share Good for Competitor Keywords?
It can generate visibility, but relevance and conversion rates may be weak while CPCs become high. Isolate competitor campaigns and use strict financial controls.
Does Target Impression Share Optimise for Conversions?
No. Conversion tracking remains valuable for evaluation, but visibility is the strategy’s bidding objective.
Why Is the Campaign Missing Its Target?
Common causes include a restrictive CPC limit, insufficient budget, weak Ad Rank, low search volume, narrow eligibility, policy restrictions or changing competition.
Conclusion
Target Impression Share gives advertisers an automated way to pursue a defined level of Search visibility. It can target Anywhere, Top or Absolute Top placement while using a maximum CPC bid limit as the principal financial guardrail.
The strategy is most useful for tightly defined brand and strategic-keyword campaigns where presence has a measurable value. It is less appropriate for general lead generation or ecommerce when conversions, revenue and profit are the real objectives.
Do not treat 100% Absolute Top as the standard configuration. Start with the business reason for visibility, separate the relevant keywords, set an affordable CPC limit and measure the incremental result. Higher prominence is valuable only when it produces enough additional commercial benefit to justify its cost.