Web-based Surveys Patty Nordstrom March 27, 2008

Types of Web-based Surveys Non-probability Entertainment surveys Self-selected surveys Volunteers from Internet users These surveys are usually for voting on a particular questions or an instant poll, they are not generalized to the greater population

Probability-based Intercept Every n th visitor to a site Respondents are from an request Mixed-mode Pre-recruited panels *As with all survey research, non-respondents are a problem

Presentation Screen by screen Only one question per page, respondent must answer the questions before they can continue Scrolling Respondent can see, if not the entire questionnaire, more than one question.

Advantages Cost Faster response rate Easier to send follow-ups Easily downloaded in to a spreadsheet or data analysis program

Advantages Questions can be easily randomized Complex skip patters Drop down boxes

Concerns Browsers Computer expertise of the respondent Data Security Randomization Privacy issues invitations considered spam

Common Problems Encountered Technical problems Usability problem Programming errors

Sources of Errors Sampling Coverage Non-respondents

Design of Web Survey One item per page Scrolling Simple is better Design should fit the purpose

General Principles Pretest Include an introduction, include consent if required If the survey is long, divide it into sections Use open-ended questions sparingly

Principles of Design for Web Questionnaires (Dillman, Tortora, Bowker) Welcome screen First question fully visible Conventional format similar to paper Limit line length Provide instructions for computer actions

Principles of Design for Web Questionnaires (Dillman, Tortora, Bowker) Welcome screen First question fully visible Conventional format similar to paper Limit line length Provide instructions for computer actions

Principles of Design for Web Questionnaires (Dillman, Tortora, Bowker) Instructions with individual questions, not at the beginning Do not force answers unless necessary Scrolling Progress bar Avoid questions structures that have known measurement problems

What we do at the SRC Work with PIs to collect data using web-based survey Use Perseus software to create web- based survey

Considerations Who is your audience? Is using web-based surveys appropriate? Multi-modal Cost

Technical Support Programmer/analysts on the staff Hardware to support data collection

Types of Surveys Open Anyone can answer access the survey and answer the questions Closed Unique IDs are assigned to individuals

Results Data is collected in a table Provide the data in various formats to PI Database (.mdb) SPSS (.sav) Tab separated (.tsv,.txt) Comma separated (.csv) Excel (.xls)

Conclusions Web-based surveys are a tool to collect data Sound principles must back up any type of data collection