SURVEYS

Surveys are the Most Flexible Means of Obtaining Data from Respondents

Surveys are the Most Flexible Means of Obtaining Data from Respondents

Introduction

Conducting a survey is often a useful way of finding something out, especially when 'human factors' are under investigation. Although surveys often investigate subjective issues, a well-designed survey should produce quantitative, rather than qualitative, results. That is, the results should be expressed numerically, and be capable of rigorous analysis.

This article describes some of the issues that the experimenter must confront when designing a small scale survey. By 'small scale' I mean one that can be carried out by a single person in a few weeks. We are very often underestimating how difficult is to carry out a survey well; a good survey is more than a handful of questionnaires and a couple of bar charts: it requires careful planning, methodical application, and detailed analysis of the results. In most surveys some statistical analysis will be required.

Perhaps this article should have been called 'how to start thinking about conducting a survey'. There is no general procedure that can be followed and which will automatically result in a good survey; all this article sets out to do is to bring the potential problems.

Sample Survey

Why do we use sample surveys? We have no choice when the population is continuous (that is, effectively infinite), but we can define a sample from either a finite or an infinite population. Surveys are done for several reasons. A sample survey costs less than a census of the equivalent population, assuming that relatively little time is required to establish the sample size. Whatever the sample size, there are 'establishment costs' associated with any survey (Borrington and Stimpson, 1999).

The following are the main stages in survey and sample design:

State the objectives of the survey

Define the target population: Defining the target population can be relatively simple, especially for finite populations

Define the data to be collected

Define the required precision and accuracy

Define the measurement 'instrument': The measurement instrument is the method - interview, observation, questionnaire - by which the survey data is generated.

Define the sample frame, sample size and sampling method, and then select the sample.

The sample frame is the list of people ('objects' for inanimate populations) that make up the target population; it is a list of the individuals who meet the 'requirements' to be a member of that population. The sample is selected from the sample frame by specifying the sample size (either as a finite number, or as a proportion of the population) and the sampling method (the process by which we choose the members of the sample).

Objectives of a Survey

The objectives of a survey can usually be phrased in the form of questions:

Which word processor do most people use?

How long does it take to learn to use WordPro?

Why do people prefer one product over the other?

On the whole questions that start with 'Why...?' tend to be harder to answer than those that start with 'Which...?' or 'What...?' Sometimes we usually have to be translated into ...