We have a conviction at COHDA :

Launching a survey without in-depth preparation is like hoping to cross the Pacific Ocean on a paddleboard – there’s little chance of getting very far! In other words, a successful study begins with choosing the right method and cannot be designed without working alongside your teams. To meet your requirements, our multidisciplinary team, organised according to various fields of expertise (sales, marketing, statistics and production) and a seamless structure fostering the diversity of skills and viewpoints can define the best approach and advise you in :

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The study technique to choose :

Mystery survey, benchmark study, mirror survey, quality monitoring, in situ information gathering, etc., there is a vaster range of investigation techniques available to you than you might think.

Evaluation frequency :

Hot or cold, barometric, one-shot, etc., because establishing temporality is key to engaging customers, employees or citizens more effectively.

The collection method(s):

Closely linked to the study theme, to the aims of the device, the allocated budget and the audience to be surveyed (BtoB, BtoC, specific niches, ultra-targeted consumers, etc.), this is a strategic factor !

The design of the questionnaire or evaluation grid :

The choice of wording, the duration, question hierarchy techniques, evaluation scales, etc., are just as important, regardless of the chosen collection method (telephone, online, social media, SMS, and so on) and imply appropriate formulation and register.

The sampling method :

Representation of the population (random method, quotas, judgemental sampling, etc.), exhaustive exploitation, oversampling of strategic targets, and so on; these are decisive considerations for the exploitation and extrapolation of results. 

File strategy :

Where necessary, we can make use of the best contact files on the market and/or enrich your own files.

Frequently asked questions :

Our BtoB or BtoC files can come from several sources :

  • The files that our clients provide, which must be Op’tin (meaning that the individual has given their consent to be contacted)
  • Files we rent from partners, in compliance with the GRDP, containing landline numbers, mobile numbers or email addresses, and meeting jointly defined criteria relative to the specificities of the survey (place of residence or location, activity sectors, payroll size, etc.)

The size of the sample is a compromise between several requirements, including :

  • The size of the reference population
  • The volume of the file to be used
  • The need to extract not only global results but also per sub-population
  • The required level of statistical accuracy
  • Cost management

COHDA guides you in this choice of methodology.

When the General Regulation on Data Protection (GRDP) came into effect in 2018, COHDA reiterated its engagement relative to data protection and took the necessary measures to comply with the GRDP, with a renewed definition of its contractual client relations and a set of provisions including :

  • The limiting of personal data collection to that which is strictly necessary for the purposes of the survey (reinforced principle of minimisation)
  • The safeguarding of respondents’ greater rights (right to information, access, rectification, deletion and transfer)
  • The strengthening of consent and the conservation of proof of consent
  • The implementation of a secured exchange platform (COHDA CLOUD) via which all files containing personal data must transit
  • The securing of premises and information systems
  • The appointment of a Data Protection Officer (Olivier MAROUANI, o.marouani@cohda.fr)
  • The hosting of data collected in France
  • The roll-out of an in-house awareness and training campaign
  • Conformity checks of its suppliers’ GRDP

GRDP is everyone’s concern, and in particular data processing professionals ! For further information, please contact our DPO.

In awareness of the risks linked to a major failure in our Information System in a broad sense and/or a significant absence of staff, we have established a Business Continuity Plan (BCA) in collaboration with our various service providers, in order to ensure the continuity of our activities, in degraded mode if necessary, despite the loss of critical resources, followed by their recovery. This plan is updated on a regular basis and can be provided on request to our clients or prospects. The most recent point to be integrated in our BCP concerns the measures to be taken in a health crisis.

All our telephone surveys are produced at our premises in Bouscat (near Bordeaux), including overseas surveys, for which we use bilingual or native interviewers according to the countries in question.

The cost of a survey depends on several parameters: the interview method (telephone, online, face-to-face, postal, social media, etc.), the number of individuals to be surveyed, the length of the questionnaire, the target profile (BtoB vs BtoC, specific targets such as young people, sensitive audiences, etc.), the quota, the file available and the geographical perimeter (France, French Overseas Territories, international surveys). It is not possible to provide the cost of a survey without taking all these factors into account, but our sales department will be happy to provide you with a quote adapted to your needs.

Unfortunately, not everyone we try to interview responds; some are absent, some refuse to respond. The ‘response rate’ varies greatly according different factors, such as: the target population (it is more difficult to obtain the participation of a company manager or a surgeon than a pensioner), the length of the questionnaire, the theme of the survey and form of collection (online, telephone, postal, etc.). With the growing trend for consultation, however, respondents are relatively cooperative once our method is not assimilated with sales prospecting.

Tele-enqueteurs cohda au bureau

“We’ve been entrusting all our surveys to COHDA for 3 years. Their expertise and advice have enabled us to accurately measure our customers’ satisfaction and thus improve our offer year after year. What’s more, their professionalism transmits an excellent image to our customers interviewed.”

— Philippe Chedru, CEO of OXYMETAL

“The COHDA team combine attentiveness and proactiveness, two essential qualities for a service provider responding to a public market.”


“COHDA stands for professionalism, attentiveness to the client and high-quality work. Each time we’ve called on them, they’ve met our requirements with efficiency and quality. I can recommend them wholeheartedly.”

— Patrick DUFOUR, Member of the Executive Board of CEAPC

“Optimal collaboration despite the distance, professionalism, proactiveness and attentiveness.”

— Lucile WEILL-BARILLET, Research Officer at ADEUS

“In 6 years of collaboration, I’m highly satisfied with COHDA’s dedicated and professional guidance. The project manager is very attentive, proactive and follows up on the file as required. We’ve built up a true relationship of trust.”

— Isabelle BAUDELET, Marketing Action Officer at UEM

“The COHDA Institute adapted perfectly to the exceptional situation of the first lockdown, in particular by implementing the necessary tools to ensure service quality.”

— CB, Statistical Studies Officer for the REGION GRAND EST regional authority

“A very serious company which demonstrates a high level of availability for its clients. COHDA has managed to meet our requirements perfectly and to adapt whenever necessary. I’d recommend COHDA without any hesitation.”

— LM , Housing Research Officer at ADIL DES BOUCHES DU RHÔNE

“A huge thanks for your involvement and proactiveness to all the team, which I have the pleasure of working with each time we call on you for a survey! Your programmer is a magician and when listening in, we were impressed by the interviewers’ professionalism in adapting to our environment.”

— Sylvie DANILO DURAN, Head of Marketing & Communication Studies at INNOVAL

Discover our profession

From the design of tailor-made tools to the collection and analysis of data, COHDA takes great pride in advising you throughout every step of the implementation of your project, in compliance with rigorous procedures ensuring quality, rapidity and security (GRDP and ethics policy, CSR, application of the ESOMAR code of conduct, etc.).

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Designing a survey device

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Data collection

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Results analysis,
presentation and advice

Proud to have worked alongside more than 250 clients

A generalist study institution, we operate in numerous sectors of activity, often with very different specificities and issues, and on behalf of major groups and small-to-medium businesses, mainly in France but also overseas.

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