Survey Methodology – CAWI

All secrets, pros and cons of CAWI methodology.

Acronym of Computer Assisted Web Interviewing, it’s the web data collection for the online survey. The respondent answers the interview on his computer, tablet, smartphone or any other device with a browser.
Low costs make online survey software extremely advantageous but it’s not always the best choice.

How does online survey software work?

Respondents log in to the interview clicking on a link. The link can be published in a website or sent via email.

The respondent will display a short text introducing the survey and then he will proceed to answer the survey questions. It’s important that the online survey interface is as simple as possible and that interview questions are perfectly clear.
The survey can be anonymous or use a univocal link.

Univocal link distribution.

Univocal distribution requires a different link for each respondent. The online survey software is then able to link respondents profiles in the database with interviews completed.

This procedure is useful to get information as who completed the survey and who didn’t complete it. Tracking survey responses is important to perform mass actions on the database, for example to send a reminder to all those who didn’t answer the questionnaire.

Univocal link and quotas.

Univocal link distribution is also useful to create surveys with quotas based on data already known. Let’s see an example: we want to complete 1000 interviews, half for females and half for males. When a quota is full, the online survey tool will stop unnecessary interviews (called over quota).

If we know the gender in advance, the software will automatically stop respondents of a completed quota with an alert, avoiding useless interviews.
When quotas are based on existing data, the univocal distribution is essential for the system to discard irrelevant contacts in real time.

Sending email to irrelevant respondents can be also avoided using a unique feature in IdSurvey. This characteristic optimizes survey distribution and saves you a lot of time and money.

Anonymous distribution.

In anonymous distribution there’s no connection between the respondent and the interview. This method is useful when you have to guarantee anonymity to your respondents. In this case all the contacts will use the same link to log in. It can be published in a website, in social media or sent via email.

It’s good to remember that anonymous distribution doesn’t prevent the same respondent to answer the questionnaire multiple times corrupting final data.

How is the distribution made with online survey software?

You can send invites to a list of respondents with an email address. A software with an integrated email sender also gives you information on opened emails or, for example, on people who didn’t receive the email because of a full mailbox or a wrong email, etc…

Carefully selecting the online survey software is really important as just a few of them have the integrated email feature. This integration is crucial to easily manage the entire survey. In fact, in some of these software you can also schedule reminders to all respondents who didn’t answer the survey.

Public link
You can publish the link in any website or social media. This method is frequently used along with anonymous distribution.

A panel is a container of outlined respondents that can be periodically interviewed for market research. We usually consider a representative sample of a specific category to be a panel and panels can really useful to make frequent surveys.

The term panel is used today to define any list of respondents available to join and answer surveys in exchange for prizes or money. There are several services of this kind as Toluna and Research Now that offer their respondents for surveys of any nature.

There are also specific software to manage your own panel. For example, a company can create a panel with their own customers to design marketing strategies, check customer feedback or to test a new product or brand. Surveys based on panels perfectly integrate with CAWI methodology because they can considerably increase response rate.

Almost any CAWI system is now able to interact with panel services as that’s more a procedure than a proper feature. But you have to keep in mind that just some of those can really make the procedure simple allowing you to set everything up in a few clicks.

Recent statistics confirm that an high percentage of web respondents answers the interview with a smartphone. It’s essential that your survey software has mobile friendly survey templates: ask your provider if they used a responsive design so that the interview template can be correctly displayed on any device.


Costs of CAWI surveys are extremely low and limited to the cost of the software and the tool to send emails.
You can find several online survey software with different policies of purchase. From low cost – with a small monthly subscription – or free version to professional – with a cost per interview. If you just have to administer short questionnaires with simple logic path, then a low cost solution may be enough. To that you have to add a service to send emails like Mailchimp.

If you want to administer surveys of medium/high complexity and get an adequate assistance, then you have to purchase a professional software. When you choose a professional software you have to look at the cost of the single interview, the setup and an integrated email sender (other than technical characteristics and ease of use).

IdSurvey has a scalable purchase policy with no activation or maintenance cost so it’s perfect for both sporadic users and professionals that administer hundreds of thousands interviews per year.


As said, CAWI software has lower costs compared to other methodologies. No costs for the interviewers and no cost for the stations mean reducing survey costs a lot.
Another benefit of a web survey is how quickly you can collect data. In fact, the user is usually lead to click on the link immediately after he read the email.

Unfortunately there are also downsides. In CAWI methodology there’s no interviewer so no intermediary figure – differently than other methodologies. This implies a number of downsides that we have to keep in mind.

For example, the user will be tempted to drop the interview if it’s really long or to give random or hurried answers. For this reason it’s important to have short, simple and direct survey design, avoiding all text bias.

Another peculiarity of CAWI surveys is the low ratio between invites and completed interviews. Depending on the quality of the emails you have, the percentage of completed interviews range between 2% and 5% of the invites sent.
Because of prizes and rewards offered, surveys administered to panel respondents have an higher response rate.

Online Survey Pros

  • Low costs
  • Possibility to use multimedia or interactive question types
  • Short duration

Online Survey Cons

  • Not suitable for long or complex surveys
  • Answers not always accurate: respondents can answer with a random option or with “don’t know” answer
  • No feedback on errors on the survey creation
  • People with no internet connection or not familiar with computers/mobile devices cannot be interviewed
  • Low response rate