Survey Methodology – CAPI

All secrets, pros and cons of CAPI methodology.

CAPI software acronym of Computer Assisted Personal Interviewing software, it’s the face-to-face data collection. An interviewer administers the questionnaire to the respondent and marks down answers on his smartphone, tablet or pc. Data are then synchronized with the server and they will be available for the analysis.

How does CAPI methodology work?

To collect data you need an application that can interact with the main software. The CAPI system app can be installed before handing over the device to the interviewer or it can be downloaded directly by the interviewer from the Google Play or App Store. Once the app is installed, the interviewer can log in to work on the survey assigned with credentials provided.
They can collect answers from random respondents (anonymous distribution) or from a list assigned by the administrator.

Anonymous distribution.

CAPI Anonymous distribution is the one to administer the questionnaire to random people, as supermarket or store shoppers, voters at polling stations, visitors in a museum/event or to passersby in the street.
At the beginning (or end) of the interview some personal data are usually requested as the name, surname and telephone number. This procedure is used to create a list of respondents for other surveys or for marketing actions.

Distribution to an existing list of respondents.

This distribution mode makes CAPI methodology really similar to the telephone one except for the fact that the respondent is interviewed face-to-face and not by phone.
The interviewer has to select the contact from the list before starting the interview with CAPI system.

Offline and online CAPI.

Before you purchase your CAPI software it’s important to get this difference. An internet connection may not always be available when you go on the field. For this reason it’s crucial to choose a software that has an app able to work in offline mode too.

This type of app is called CAPI offline and lets you collect data with no connection at all.
It’s possible to collect as many interviews as you want and then synchronize them with the main server when you have a data or WiFi connection.

Apps that don’t support offline mode cause a lot of issues for CAPI methodology.
Sometimes they’re erroneously called CAPI online and they’re not useful at all for this methodology. Quite often they’re developed using existing material from CATI or CAWI interface: the investment of the software firm is minimal but the result is useless. It’s really important not to fall into a trap and be sure that the software you’re purchasing supports real CAPI – that is to say – an offline app.

Mistery shopping.

Mystery Shopping is an activity used by big organizations to check on service quality, customers satisfaction or product quality on their commercial network using fake customers to evaluate any aspect of their stores. This methodology is crucial to collect important information and it’s considered to be essential to keep quality standards high.

The fake customer can quietly complete the questionnaire using a smartphone or a tablet and take pictures to verify products display or rate service quality adding notes to any aspect they have evaluate. CAPI apps (those that can take photos or save the gps location in particular) are really useful to save information collected during the mistery shopping activity.


When you estimate costs for a CAPI survey you have to keep in mind those related to the software, the devices and the interviewers. The cost of the software is difficult to calculate as it may differs a lot depending on the license policy.
Some firms have a subscription option to pay for each interviewer while others have it only for the interviews. We suggest to opt for the latter as you’ll have definite costs and great flexibility.

The costs of the mobile devices for CAPI surveys can be easily voided if you ask the interviewers to use their own smartphone, tablet or PC. In this case, you need to select a CAPI app that is compatible with all major operative systems as Android, iOS and Windows PC. If you want to opt for company devices, you have to consider around 200/300€ for each interviewer, depending on the model selected.


  • Accurate answers
  • Reliable information on respondents
  • Almost the entire population can be reached
  • You can interview people you didn’t know before: customers of a mall, passersby, etc…
  • You can interview respondents from rural areas
  • The presence of the interviewer discourages the interview dropout
  • With an appointment the interviewer can reach categories difficult to reach as lawyers or MDs
  • Interviews can be longer as the drop out rate is lower
  • Direct contact between the interviewer and the respondent
  • The interviewer can be trusted for sensitive topic
  • The interviewer can help in questionnaire comprehension
  • Discourage the don’t know/don’t answer
  • Respondent’s reactions can be noted
  • No data entry costs in respect to the old PAPI methodology (interviews on paper)


  • Costs for the interviewers
  • Costs for the mobile devices (if interviewers don’t use their own)