Basic Overview of ACA

ACA for the Web lets the researcher design a computer-interactive conjoint interview for data collection over the Web, an intranet, or using CAPI-based (stand-alone PC) interviewing. The interview can consider many attributes and levels, paying special attention to those the respondent considers most important. Questioning is done in an "intelligent" way; the respondent's part-worths are continually re-estimated as the interview progresses, and each question is chosen to provide the most additional information, given what is already known about the respondent's values. In addition to the conjoint-related ACA questions, ACA comes with a CiW/50 system that can include up to 50 "standard" survey questions for capturing additional information for use in market segmentation. These 50 questions can include randomizations and skip patterns. (More than 50 questions can be fielded in conjunction with ACA through larger CiW licenses. Both CiW and ACA are products within the SSI Web suite of Web interviewing products.) Respondent data are saved to a database on the Web server (or on separate PCs, if using CAPI-based data collection), and are available in real-time upon completion of the interview.

ACA was developed using established industry-standard technology (Perl and HTML) available on most Web servers. The interviews can be completed on nearly any Web browser. The steps for designing and conducting an ACA study are typically as follows:

1.

Using a Windows-based tool running locally on a PC (without being connected to the Web), the researcher designs the ACA study: types in the attributes and levels, adds additional survey text, and chooses from a menu of options that control the overall flow of the interview. The researcher formats questions using the point-and-click interface and views the questions one page at a time using Internet Explorer. Additionally, the researcher creates a table of passwords to assign to respondents and quotas for each password combination.

2.

Once the researcher is satisfied with the look, flow and content of the interview, the interview is uploaded onto a Web (or intranet) server (or, optionally, to multiple PCs for CAPI-based interviewing). The online help includes detailed instructions regarding the directories, files and permissions that must be included in the installation.

3.

The researcher tests the ACA survey online by accessing the interview over the Web (or intranet) using a Web browser, making sure the interview is administered as expected, and checking the resulting data using the Admin Module to ensure that the data are being stored correctly. A pretest is often conducted during this stage to evaluate the suitability of the survey and to make sure the resulting utility data have face validity.

4.

Respondents are invited to participate in the survey (usually via email) and are given the URL address and password. While the interview is in progress, the researcher and/or client can view or download the data at any time without disturbing the data collection or interviews that may be in progress.

5.

When interviewing is complete, the data are downloaded using SSI Web's Admin Module, and the respondent utilities are estimated using ACA's utility calculator locally on the researcher's PC (or using ACA/HB software for hierarchical Bayes estimation). The researcher then uses either the Online Market Simulator or the Market Simulator software included with the ACA software to analyze the results and conduct market simulations.