Computer-assisted personal interviewing (CAPI) is an interviewing technique similar to computer-assisted telephone interviewing, except that the interview takes place in person instead of over the telephone. Either the respondent or the interviewer sits at a computer terminal and enters the answers. If no interviewer is present, the term Computer-assisted self interviewing (CASI) may be used.

• Either the respondent or an interviewer sits at a computer terminal and answers a questionnaire using the keyboard or mouse.
• Help screens and courteous error messages are provided.
• Colorful screens and on and off-screen stimuli can add to the respondent's interest and involvement in the task.
• This method has been classified as a personal interview technique since an interviewer is usually present to serve as a host and to guide the respondent.
• This approach is used in shopping malls, preceded by the intercept and screening process.
• It is also used to conduct business-to-business research at trade shows or conventions.

For example, CAPI is used as the method of data collection for the British Crime Survey

British Crime Survey

The British Crime Survey or BCS is a systematic victim study, currently carried out by BMRB Limited on behalf of the Home Office. The BCS seeks to measure the amount of crime in England and Wales by asking around 50,000 people aged 16 and over , living in private households, about the crimes they...

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Advantages

This form of interview is substantially cheaper when a large number of respondents is required, because

• There is no need to recruit or pay interviewers.
• There is no need to transcribe the results into a computer form. The computer program can be constructed so as to place the results directly in a format that can be read by statistical analysis programs such as PSPP
  PSPP
  PSPP is a free software application for analysis of sampled data. It has a graphical user interface and conventional command line interface. It is written in C, uses GNU Scientific Library for its mathematical routines, and plotutils for generating graphs....
  
   or DAP
  DAP (software)
  Dap is a statistics and graphics program, that performs data management, analysis, and graphical visualization tasks which are commonly required in statistical consulting practice....
  
  .
• The program can be placed on a web site, potentially attracting a world-wide audience.

Disadvantages

• The survey is likely to attract only respondents who are "computer savvy", thus introducing potential bias to the survey.
• The survey can miss feedback, provide clarification/quality control that a personal interviewer could provide (ex. lots of respondents think the question asks one thing, when it actually asks another)

Computer-assisted self interviewing

The big difference between a computer-assisted self interview (CASI) and a computer-assisted personal interview is whether or not an interviewer is present. There are two kinds of computer-assisted self interviewing, namely a "video-CASI" and a "telephone-CASI". Video-CASI are often used to make a complex questionnaire more understandable for the person that is being interviewed. Audio-CASI has the same advantage, but could also reduce problems that interviewees have with literacy.
Furthermore, both types have a big advantage over computer-assissted personal interviewing, because subjects are more inclined to answer sensitive questions. The reason for this is that they feel that a CASI is more privative.