Regulatory Compliance

Reviewing No. 1 claims, comparative advertising, and satisfaction claims

Whether claims such as "No. 1 in sales," "No. 1 in customer satisfaction," "90% satisfaction," and "X times more than competitors' products" may be published cannot be determined merely because rankings or percentages have been calculated. The content of the claim needs to correspond to what was surveyed, what it was compared with, who was surveyed, and how the survey was conducted.

The Consumer Affairs Agency (CAA) states that No. 1 claims raise issues as misleading representations if they lack reasonable grounds and differ from the facts, and its September 2024 report on a fact-finding survey identifies the elements needed for reasonable grounds. For comparative advertising, three requirements have been set out: objective substantiation, accurate and appropriate quotation, and a fair method of comparison.

We check survey designs, questionnaires, tabulation materials, and reports against proposed advertisements, and assist with considering what claims can be made and whether revisions are needed. The report states that responsibility for misleading No. 1 claims rests with the advertiser even if the survey has been outsourced to a research company.

Reviewed by Keishi Yoshikawa, Attorney at Law and Patent Attorney (Dai-Ichi Tokyo Bar Association)

Last updated: September 27, 2026

What to check first

The following are examples of matters a company may wish to check when reviewing No. 1 claims or comparative advertising.

The metric emphasized — The company checks which metric the claim emphasizes, such as sales value or volume, satisfaction, willingness to recommend, or awareness.
Subjects and scope of the comparison — The company checks whether the products or services, geographic areas, sales channels, and periods covered by the comparison correspond to the scope of the claim.
Survey respondents — The company checks how respondents were selected, their experience using the products or services, their ages, and other characteristics.
Questions and presentation — The company checks the actual question wording, answer choices, images or websites shown, and the order of presentation.
Tabulation methods — The company checks when the survey was conducted, the number of responses, the criteria for valid responses, the denominator, and the methods used for tabulation, exclusion, and rounding.
Available materials — The company checks whether it can obtain the materials needed for its assessment, including the questionnaire and a breakdown of the tabulated results, and not only the survey report.
Scope of claims that can be made — The company checks whether the rankings, percentages, and conditions of comparison stated in the advertising go beyond what the survey results support.
Review after publication — The company checks the plans for reviewing the claim in light of product changes, changes in competitive conditions, or doubts about survey results that arise after publication begins.

If the survey has not yet been conducted, the questionnaire and the selection of respondents can be checked at the design stage.

How we can helpReviewing survey designs and questionnaires / Checking survey results against proposed claims / Reviewing comparative advertising / Identifying matters to check with the research company / Reviewing claims after publication

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Contents

1 Identifying what the claim conveys
2 Checking the basis for No. 1 claims against four elements
3 Reviewing comparative advertising and percentage claims
4 Checking with the research company and reviewing claims after publication
Key legislation and official sources
Frequently asked questions

1 Identifying what the claim conveys

Objective metrics such as sales value and volume

When stating a ranking by sales value, sales volume, number of users, or similar metrics, the company clarifies the product range, geographic area, sales channels, and period covered by the tabulation and aligns these with the ranking claimed.

Subjective evaluations such as satisfaction and willingness to recommend

Satisfaction among actual users, an intention to use a product or service in the future, and impressions of a website are different types of evaluation. The report identifies as potentially problematic cases where "No. 1 in satisfaction" is claimed even though only a survey asking about impressions (a so-called "image survey") has been conducted, rather than a survey of actual users.

Scope of the claim

The company checks whether results limited to particular products or conditions of use are presented as an evaluation of the brand or service as a whole.

2 Checking the basis for No. 1 claims against four elements

The report identifies four elements of reasonable grounds for No. 1 claims: appropriate selection of the products or services being compared, appropriate selection of survey respondents, a fair survey method, and appropriate correspondence between the claim and the survey results.

Selecting the products or services to compare

The report identifies surveys that exclude some or all of the major products or services in the market from the comparison as examples that cannot be regarded as based on reasonable grounds and may raise issues. The report states that, for reasonable grounds to exist, at a minimum, products or services of the same or a similar kind that should be compared need to be appropriately selected, and the ranking relative to those products or services needs to be surveyed. The company clarifies how the category name used in the claim relates to major competing products and checks which products were excluded from the comparison and why.

Selecting survey respondents

The report also identifies surveys limited to customers who purchase the company's products or services on an ongoing basis, or surveys of the company's own employees or other people associated with it, as examples that cannot be regarded as based on reasonable grounds and may raise issues.

Fairness of the survey method

The company checks whether the question wording, materials shown, answer choices, or order of presentation have steered respondents toward particular answers, and whether the survey has been repeated until the desired result was obtained. The CAA's views on comparative advertising state that the method and extent of substantiation are assessed in light of matters such as the characteristics of the products or services compared and the scope and degree of the advertising's impact. They give examples in which comparative advertising about consumer preferences for the company's products and competing products across a fairly wide geographic area requires a survey with a substantial sample, while a relatively small sample is sufficient for a small or medium-sized enterprise running comparative advertising for low-priced products in a limited geographic area. The company asks the research company about the sample size, sampling method, margin of error, and how differences in rankings are evaluated.

Correspondence between the claim and survey results

The company checks whether the questions asked, the scope of the survey, and the tabulated results correspond to the meaning of the ranking or evaluation conveyed in the advertisement. The report identifies appropriate correspondence between the claim and the survey results as an element of reasonable grounds, and gives examples in which a "No. 1 in customer satisfaction" claim may raise issues if that correspondence is lacking, even when accompanied by a note. In our view, whether a tied result is presented as an outright lead, or a narrow difference as a substantial advantage, is assessed on the basis of the claim as a whole, including its wording, notes, and scope of comparison.

3 Reviewing comparative advertising and percentage claims

The three requirements for comparative advertising

The CAA's views on comparative advertising state that, for comparative advertising not to constitute a misleading representation, it must satisfy three requirements: objective substantiation of the claims made, accurate and appropriate quotation of substantiated figures and facts, and a fair method of comparison.

Objective substantiation and accurate and appropriate quotation

Substantiation needs to use an established method where one exists, or otherwise a method considered appropriate in light of generally accepted views and experience, and needs to be sufficient to recognize that the fact being claimed exists. The views also state that, when part of a survey's results is quoted, the quotation needs to be consistent with the purport of those results, and that it is appropriate to include in the advertisement information about the survey method, such as the research organization, when the survey was conducted, and where it was conducted.

Fairness of the method of comparison

An advertisement may constitute a misleading representation if it emphasizes overall superiority based on a comparison of a particular feature that has little bearing on overall functionality or similar characteristics, or if it compares items not regarded as equivalent while presenting the comparison as one between equivalent items. The same applies where a disadvantage inseparably linked to an advertised advantage is deliberately omitted or not clearly disclosed.

Percentage claims such as satisfaction rates

The report states that claims indicating the percentage of favorable evaluations, such as "90% satisfaction," differ from No. 1 claims based on subjective evaluations because they do not necessarily presuppose a comparison with other products, but that the approach to reasonable grounds is basically the same. For claims that a product is recommended by experts such as doctors, the report considers such claims to indicate that the experts recommend the product as a judgment based on their professional knowledge and objective data about the product's quality and content. The company therefore checks whether the question wording, answer choices, responses combined in the total, and denominator correspond to the meaning conveyed by "satisfied," as well as what information was provided to the recommending experts and how their fields of expertise relate to the product.

4 Checking with the research company and reviewing claims after publication

Materials for the advertiser to check

The report states that responsibility for misleading No. 1 claims rests with the advertiser even where a third party, such as a research company, has conducted the survey supporting the claim. It also reports instances in which advertisers decided to make claims after being approached by research companies, without sufficiently checking the survey's content. The company obtains and reviews the questionnaire, information on how respondents were selected, and a breakdown of the tabulated results, and not only the report.

How to present the survey conditions

The report states that it is desirable to allow general consumers to check the details of the survey supporting a claim, and identifies displaying an outline of the survey method in the advertising material as one way of doing so. The placement and visibility of notes are explained in "Assessing advertising content: prominent claims and disclaimers."

Continuing to use survey results

The company checks whether past survey results can continue to be used in light of changes to the product, changes in competing products, and the results of new surveys. The CAA's views on comparative advertising identify presenting a survey conducted a considerable time ago as if it were recent as an example that may constitute a misleading representation. The company checks whether the claim presents a past result with the month and year of the survey, or conveys that the product is currently in first place, and considers the claim in light of changes to the product and the competition since the survey.

If doubts arise about the basis for a claim

The company identifies where the claim appears and the survey on which it relies, and then considers revising the claim or stopping its use. Corrective action and responses to authorities are explained in "Alleged violations of the Premiums and Representations Act, voluntary correction, and regulatory responses."

Key legislation and official sources

English translations of legislation are provided for reference. The Japanese texts are authoritative.

Article topic	Legislation or official source	Source type and English version reviewed
Misleading representations, including No. 1 claims, comparative advertising, and satisfaction claims	Act against Unjustifiable Premiums and Misleading Representations— Japanese text on e-Gov	Legislation. English translation (earlier version). The translation identifies its last version as Act No. 29 of 2023.
Four elements of reasonable grounds for No. 1 claims; percentage claims; recommendations by experts; advertiser responsibility; presenting survey information	Report on a fact-finding survey of No. 1 claims, September 2024	CAA report (Japanese). English title translated by the firm.
Three requirements for comparative advertising; substantiation and sample size; quotation; fair comparison; older surveys	CAA views on comparative advertising	Official guidance (Japanese). English title translated by the firm.

Legal information reviewed: September 27, 2026

Frequently asked questions

Can a claim be published if the research company says, "There are no problems with this No. 1 survey"?

Responsibility for misleading No. 1 claims rests with the advertiser even where a third party conducts the survey. The advertiser needs to check for itself whether the survey's content corresponds to the claim.

Can "No. 1 in customer satisfaction" be claimed on the basis of a survey asking about impressions of a website?

The report identifies as potentially problematic cases where "No. 1 in satisfaction" is claimed even though only an image survey has been conducted.

Are 100 respondents enough for a survey?

Neither the report nor the CAA's views on comparative advertising set a fixed number of respondents that is sufficient in every case. The number is considered in light of what the survey covers, the scope of the claim, the sampling method, and other relevant factors.

Can a "No. 1" claim be made when the result is a tie for first place?

The report calls for the content of the claim to correspond appropriately to the survey results, and gives examples of "No. 1 in customer satisfaction" claims that may raise issues where that correspondence is lacking, even if a note is included. The company also considers stating clearly that the result is a tie and explaining the scope of the comparison, and checks whether the claim as a whole could be understood as claiming sole first place.

Is comparative advertising that names a competitor's product prohibited?

Comparative advertising is not prohibited as such, and the CAA's views on comparative advertising set out the requirements for comparative advertising not to constitute a misleading representation. The company considers whether the three requirements (objective substantiation, accurate and appropriate quotation, and a fair method of comparison) are met.

Can positive responses be combined to make a "90% satisfaction" claim?

The company needs to check whether the question wording, answer choices, responses included in the total, and denominator correspond to the meaning conveyed by "satisfied."

Contact

Making an inquiry

Please let us know, as far as you are able, the proposed advertisement, the survey report, the questionnaire, the tabulation materials, and your communications with the research company.