to the topic of the survey, it should be borne in mind that NSIs and other government statistical bodies collect data primarily for policy decisions. There may be different surveys for different social and economic indicators. Many surveys are compulsory, which means that the contacted elements are obliged to respond. If they do not, they may be fined. Sometimes questionnaires are rather complex since many topics are covered. Surveys conducted by academic researchers, market research organizations, and other companies tend to be more heterogeneous, covering a number of different issues: product characteristics, customer satisfaction regarding products and services, employee satisfaction, trends in consumer preferences or behavior, health, use of technological products, and so on. Generally speaking, survey topics dealt with by this type of survey administrator are mainly devoted to a more or less traditionally defined target population, and therefore an appropriate survey frame definition becomes more difficult. Surveys carried out by this type of survey administrator could often make use of a simpler and shorter questionnaire.
With respect to the distinction between cross‐sectional and panel data collection, it should be noted that cross‐sectional surveys gather data about one moment in time, whereas panel surveys collect information at many successive points in time with the focus on investigating changes over a period of time. Panel surveys are discussed in Chapter 14. The main problem with panel surveys is the lack of representativity of the panel and of the samples selected from it. The real world is full of panelists recruited by means of self‐selection and therefore not representative for the population. In this case, the panel is a large group of elements that is approximately as large as the population, but the large size doesn't imply representativeness. Large probability‐based panels are representative, but more difficult to recruit.
If a panel is for longitudinal studies, all respondents are tracked back to the moment they entered the panel. Therefore, when doing a longitudinal analysis of survey results, DiSogra and Callegaro (2009) recommend computing cumulative standardized response rates (taking into account different recruitment waves), i.e., rates based on a multiple recruitment approach. This approach captures the dynamics of a panel member's history with regard to nonresponse and attrition, i.e., of loss of respondents of the recruited panel.
With regard to technical implementation of the questionnaire, there are two approaches possible i.e. online data collection and offline data collection:
Online data collection is a way of data collection for which the respondents have to remain online during the process of answering the questions. The questionnaire is implemented as one or more web pages. The respondent has to surf to the survey website in order to start the questionnaire. The questionnaire can be question based or form based. Question based means that every web page contains a single question. After answering a question, the respondent proceeds to the next question that is on the next page. If the questionnaire contains routing instructions and consistency checks, we recommend the page‐based approach. Form based means that there is a single web page containing all questions. This page looks like a form. Usually there are no routing instructions and no consistency checks. The questionnaire can be optimized for the mobile devices; in such a case, questions are presented in a user‐friendly format for reading and completing in smartphones or other devices.
Offline data collection. The electronic questionnaire form (an HTML page, an Excel spreadsheet, or another of interviewing software tool) is send to the respondent by e‐mail, or the respondent can download it from the Internet. The respondent fills in the form or spreadsheet offline. After completing the questionnaire, it is returned (uploaded, send by e‐mail) to the survey agency. Statistics Netherlands, for example, used this approach for a number of business surveys. A computer‐assisted interviewing program was send to the selected businesses. The businesses run this program offline and answer the questions. After completion, contact is with the Internet again, and the data are uploaded to the survey agency.
In the case of an electronic form, the advantages of a printable questionnaire can be combined with those computer‐assisted interviewing (routing and consistency checking). Note that it is also possible not to bother the respondents with consistency checking. This means no errors will be detected during form completion. However, errors may afterward be detected by the survey agency, possibly resulting in returning the form to the respondent for error correction. This is much less efficient.
2.2.2 WHY ONLINE DATA COLLECTION?
The challenges of the online surveys have been recently increasing due to the explosion in the Internet use and of mobile devices. Potential advantages of this data collection mode are interesting, but several disadvantages or at least methodological question are arising. Thus, the researcher needs to understand and know the methodological issues to be faced and the risks of errors. The following paragraphs are focusing on the advantages and disadvantages and related critical issues.
2.2.2.1 Advantages
Survey participants are increasingly responding to web surveys on their smartphone as opposed to their personal computers. Web or mobile web surveys combine the advantages of the web with the advantages of mobile devices. They have several advantages. The three most important advantages are that mobile web surveys are faster, simpler, and cheaper.
With respect to the time required to conduct a mobile web survey, the following observations can be made:
The time it takes to get in contact with the respondent can be considerably reduced if the invitation is sent by e‐mail or text message (SMS).
Follow‐ups can be carried out very quickly by e‐mail. The timing of reminders can be tailored to the respondents. A typical pattern for web surveys is that many completed questionnaires are returned almost immediately. The number of returns diminishes fast after a few days. Web surveys allow for a short time lag between request and reminder than mail surveys. Biffignandi and Pratesi (2002) showed that the time interval between the first contact and the first follow‐up can be shorter than in mail surveys. The intervals between successive follow‐ups can also be very short, and no more than three reminders are necessary. The fourth reminder is almost ineffective. The authors suggest that 10 days is an adequate time interval between first contact and first follow‐up, whereas the time interval between successive reminders is around 1 week. Furthermore, Crawford, Couper, and Lamias (2001) showed that a quick reminder after two days works fairly well.
The time it takes to deliver a complete questionnaire is also very short. As soon as it is completed, the questionnaire is submitted and delivered. Thus, there is no time lag between the moment the respondent returns the questionnaire and the moment it is received.
The time it takes to store the collected data is dropped. Responses are instantly recorded into a database and prepared for analysis.
To sum up, the entire data collection period is significantly shortened. All data can be collected and processed in little more than a month. There are even opinion polls on the web for which design, data collection, analysis, and publication all take place in one day. Recently, mobile web surveys are applied for in‐the‐moment research. In‐the‐moment survey administration is via mobile device (especially smartphone) in the moment and in the location of the research matter. For example, customers contact is while using the product or consuming it, while shopping or while entering or exiting a location. In this case, the results are rather immediate; the representativeness of the results has to be evaluated, subjects to be interviewed have to be selected using probabilistic criteria, and data have to be adequately processed.
A second advantage of web and mobile web surveys is that they can be tailored to the situation. Therefore they may make life simpler for the respondents and the researcher. Here are some examples:
