![]() Federov - Named after its inventor, this procedure starts with a random design which is sequentially improved by trying different questions until no more improvement is found.As the name implies, for each question a random level is chosen for every attribute of every alternative. There are two approaches to making an alternative-specific design. Although they are labelled the same, each mode of transport has its own Travel time attribute. Hence Walk shows more appropriate longer travel times than Drive. Not only are there attributes which are specific to certain alternatives, but the same attribute can have different levels per alternative. Crowding with three levels ( Empty, Half full, No seats).Wait time with four levels ( 0 mins, 5 mins, 10 mins, 15 mins).Travel time with three levels ( 20 mins, 25 mins, 30 mins).Travel time with three levels ( 10 mins, 15 mins, 20 mins).Travel time with three levels ( 30 mins, 40 mins, 50 mins).Continuing with the transport example, let's consider an experiment with the following alternatives, An example designīefore going any further, you might want to look at this Displayr document where you can follow my steps and try them for yourself. This is in contrast to a standard choice experiment, for instance choosing between sports drinks where each drink has the same attributes of cost, color, sugar content and bottle size. where each attribute label is shown exactly once per question. Often this arises with labelled alternatives, i.e. ![]() Alternative-specific design are used in such situations where the attributes that describe some alternatives do not apply to other alternatives. Drive has a Parking attribute that is not shown for Walk and Bus. Note that the attributes are different for each alternative. A typical question would be to choose between three alternatives, such as those shown below. In each question, respondents choose between alternative methods of travel to work, such as Walk, Drive and Bus. The most common example of an alternative-specific design is a transport choice experiment. Instead of every alternative having the same attributes, each alternative can have its own attributes. Alternative-specific designs relax this requirement and are designed to handle situations where alternatives are described by different qualities. In a standard choice experiment, respondents are presented with alternatives which have a common set of attributes.
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