Frequently Asked Questions and Advice
FAQs:
- What is an omnibus?
- How do I select a supplier?
- Who is interviewed by the omnibus?
- How are they interviewed?
- What background information do you collect on the respondents?
- When do I get my results?
- How do I get my results?
- What makes one omnibus supplier different from another?
- What types of omnibus could I use?
Advice:
What is an omnibus?
An omnibus is one of the most popular tools amongst researchers for finding out the views of the population, on just about anything! Its popularity is based primarily on four factors:
- It provides easy access to a representative sample of adults (so you know you're getting the views of the population at large rather than just a bunch of quirky individuals)
- It can be used to ask anything from one to thirty questions on just about any topic
- It's a good way of reducing survey costs
- It's excellent for providing survey data quickly
The basic concept of an omnibus is that the fixed costs of running a survey (which can be high) are shared amongst all users. You pay a fixed price per question (although this is negotiable for regular clients) and the omnibus supplier assumes they can sell enough questions to cover all the fixed costs - this makes it a risky business for omnibus suppliers, but a very economical and safe way for you to run your surveys.
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How do I select a supplier?
As well as the price, there are six questions you should ask when choosing an omnibus supplier:
- Who is interviewed by the omnibus?
- How are they interviewed?
- What background information do you collect on the respondents?
- When do I get my results?
- How do I get my results?
- What makes you different from other omnibus suppliers?
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Who is interviewed by the omnibus?
Most omnibus' offer a nationally representative sample of adults aged 15+, but there are also specialist surveys targeting motorists, managing directors, doctors, patients, children and so on.
The majority of consumer omnibus surveys reach at least 1000 adults per wave, but as the largest supplier we deliver 2000 adults each week. This provides a robust sample size for most analysis although it is possible to increase the sample size (particularly if you wish to target a minority sample) by running your questions over several waves of the omnibus. This can be particularly cost-effective as most suppliers offer discounts for repeat waves.
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How are they interviewed?
- The most common (and probably the most reliable) for face-to-face surveys is a random location design - with quotas set for age and working status within gender.
- There are also surveys that utilise pre-selected and quota sampling. By and large, the latter should be avoided as it is too simplistic, however, either random location or pre-selected sampling works well for omnibus research.
- Telephone surveys tend to use random digit dialling or numbers from phone books - with quotas set for age and working status within gender. Random digit dialling is the preferred method as it does not exclude any of the phone-owning population (c.90% of households have a landline phone) at the outset.
When finding out about the sample design for a face to face omnibus, always check to find out how many sampling points are used - the rule being the more the better.
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What background information do you collect on the respondents?
The amount of information provided varies by supplier so always check at the outset to see what is on offer - all will provide basic socio-demographics but some also offer fairly extensive media and internet-based data.
All of this information should be provided free of charge by the omnibus supplier and is available for you to use either for screening certain types of people into your questions or for profiling your results. Always check to see what information is available, you might even be able to save some money on questions you were going to ask as part of your survey.
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When do I get my results?
Although omnibus provides a fast turnaround for results, the best ones are very popular so do try and book as far in advance as possible.
In Great Britain the turnaround time from questionnaire agreement to receiving the results is around 10 days for face-to-face surveys and anything from three hours to three days for telephone and online surveys.
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How do I get my results?
Typically the output of most omnibus' are computer tables. The amount of flexibility you have in the design of the tables varies by supplier - as does the help on offer in setting up your analysis. You might find some suppliers restrict you to a set number of tables or are quite rigid with how you define target groups, so always check at the outset.
In addition to tables, many suppliers are happy to provide data in various formats such as Memphis Survey Explorer*, Quanvert*, ITE Fiche* and SPSS. Also available are summary reports and presentations, although these are seldom provided as standard so be sure to check if these are important to you.
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What makes one omnibus supplier different from another?
The omnibus market is competitive and from the outside it might seem several suppliers are all offering the same service. That's not the case. Many will offer additional services if pushed - ranging from free advice to new reporting software which could make your job a lot easier. Ask and you will always get more for your money!
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What Types of Omnibus Could I Use?
You will usually come across three main types of omnibus: (there are a few other specialist surveys)
- Those carried out in-home, face to face (often using CAPI or multi-media CAPI), and means the interviewer visits the interviewer in person at their home
- Those carried out by telephone
- Those carried out via the internet
Face to face omnibus surveys tend to offer a larger sample size per wave (typically 2000 adults per wave in GB) and allow you to use stimulus materials in your survey and cover subjects which might be a bit awkward over the phone (e.g. anything from health to financial topics).
Telephone omnibus surveys offer a faster turnaround time (they're about 4-5 days quicker than a face to face survey) but the downside is a smaller sample size and some restrictions on the kind of things you can cover.
Online omnibus services are often cheaper and offer an even faster turnaround time than telephone surveys. At the same time they also share many of the same benefits that face to face methodologies enjoy e.g. visual prompts, multimedia capability etc.
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Getting the most from your omnibus supplier
The cost of using an omnibus generally depends on three factors:
- The number of questions being asked
- The number of people (as a percentage of the total omnibus sample) answering each question
- The types of question being asked
To get the most cost-effective research therefore requires asking the fewest questions of your target audience in the most economical way.
Most suppliers will be happy to offer advice on designing cost effective, actionable research; but below are six tips for getting the best value from your omnibus survey.
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Tips For Getting More from your Omnibus Research
- Open-ended questions cost the most. Questions which use predefined answers with an option for "other - write in" often provide the same information at a fraction of the cost.
- Batteries of statements rather than a series of questions offer a cost effective way of covering a lot of ground in a questionnaire.
- It is often possible to combine two or more questions by presenting several answer options at one question to the respondent. For example, asking "Do you buy coffee?" followed by "What brands do you buy?" would cost roughly twice the price as just asking "What brands, if any, of coffee do you buy?".
- The classification section of an omnibus appears at the beginning of the questionnaire - you can use the information collected to target your questions on key groups rather than always ask your questions of all respondents. For example, mothers of young children or those with internet access. The more you can target your questions on certain respondents, the lower the end price.
- Check what information is provided as standard by the omnibus classification. As well as using it to target your questions you might find you can use it in place of some of your questions (some omnibus' for example provide free data on digital TV ownership, internet access, media habits etc).
- Using one supplier for international omnibus research is often more cost-effective than commissioning an agency in each country as the project management is centralised.
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