Surveys are a key tool in collecting information about a "population", whether that population is a set of people, households, businesses or even pieces of equipment. Most surveys use information from a subset or sample of the population, which if done right will lead to an understanding of the whole targeted population. Such sample surveys require proper statistical input in their design and analysis.

Surveys can be a major investment, with results often playing an important role in strategic planning decisions. Therefore, it is critical to invest in a good design, good implementation and the best analysis. Data Analysis Australia's statisticians and survey researchers have years of expertise, specialising in ensuring surveys meet the individual needs of our clients.

Data Analysis Australia consultants can advise on all aspects of survey design, implementation and reporting:

• The implementation of a survey can use a mixture of collection techniques or modes, including telephone interviews, face-to-face interviews, door-to-door interviews, self completion forms and online questionnaires. Each method has its particular strengths, weaknesses and costs and for each survey Data Analysis Australia can guide the client so the right choice is made, and the best results achieved.

• A well designed questionnaire is vital to ensure that the information collected is accurate, unbiased and, most importantly, gathers the information needed to address research issues. Analysis of past survey results can sometimes provide valuable information for a new questionnaire, eliminating ineffective questions and directing resources to areas of more value.

• Closely linked to the collection method is the issue of sampling - how is the sample that must represent the population chosen? Good sample design can minimise costs and increase the statistical power of the analysis to provide better results.

• Following on from sampling is the application of survey weighting to enable inferences to be made about the whole population. This weighting can incorporate differing sampling probabilities as well as benchmarking to known population totals.

• The analysis stage may simply be a case of generating tables of results or it can involve more sophisticated analytical techniques. The planned analysis should be kept in mind whilst developing the questionnaire, to ensure that the information necessary to undertake the analysis will be obtained. If you have data that has already been collected, we can usually devise an analysis plan to extract useful information from your data, even if it isn't exactly what was anticipated when the data was originally collected.

• Interpreting results from the analysis usually requires a formal assessment of the accuracy and significance of key results to ensure decisions are not made based on random variation. Data Analysis Australia provides interpretations and recommendations based on sound statistical principles and our consultants are well versed with the statistical theory and practice in determining the sampling error for a survey.