Effective Product Selection in Electronic Catalogs

ABSTRACT

Keywords

© 1997 Copyright on this material is held by the authors.

INTRODUCTION

Browsing is usually the easiest searching technique for casual users. If they are used to browsing the web, they know how to browse a product catalog. It is easy to explore what is available. Unfortunately, if they know in advance what they are looking for (e.g. a list of criteria the product must fulfill) or if the list of products is long, it is cumbersome to browse forward and backward to compare several product features.

Database retrieval perfectly serves users who know exactly what they are looking for. Users enter a specific query reflecting their needs and they are, in return, presented with a list of appropriate products. However, if users do not know what they are looking for, it may be difficult to proceed. Data exploration has to be done by formulating several clever database queries. This can be a prohibitively complicated task for casual users.

Incremental Restriction on Interactive Tables (IRIT) is a new technique introduced by Spenke et al. [3]. It extends Ahlberg and Shneiderman's dynamic queries [1], and Rao and Card's focus+context technique [2]. IRIT combines the advantages of browsing and database retrieval: Starting with a potentially very large table, the user can incrementally restrict the view on the table to a relevant subset of products by selecting the criteria those products have to satisfy. After each point-and-click operation the user can browse the remaining subset to get a feeling of which products are available that match the criteria given so far. Spenke et al. implemented the IRIT technique in a tool called FOCUS [3].

We studied casual users working with FOCUS to better understand the impact of the promising IRIT technique on product selection effectiveness.

SYSTEM

The interface is spreadsheet-like; columns represent products, rows represent features (product attributes). All available products are visible in the given window, although if there are many products, the columns may have a width of just a few pixels. If users want to inspect a single product, they click on the header of the corresponding column and the column is expanded to a readable width. When users select a feature (row) within this column, all other products that have the same value for that feature are also highlighted. By double-clicking on that cell, the view is restricted to those products that match this criterion. There are several other `query building' manipulations such as sorting the products by a feature or specifying a subrange of a feature for restriction.

METHOD

Hypothesis

This strategy would lead to the selection of suboptimal products in situations that are similar but more complex than the ones shown below. In Figure 1 the application of a sequential selection strategy implies that, first, feature A is considered to be relevant and is therefore selected. This operation excludes product 2 and leaves only product 1 which, however, does not offer feature B. This is a sub-optimal choice if feature B is more important to the user than feature A.

	Product 1	Product 2
Feature A	X
Feature B		X

Figure 1: Simplified FOCUS product table showing two products, each of which supports (X) one feature.

Starting from the situation in Figure 2, a sequential top-down strategy means that the user first considers A useful and selects it, thereby excluding the cheap product 2. Next, feature B is selected because it is considered even more important than A. Only the very expensive product 3 remains. The user does not become aware of the choice between obtaining both features A and B for $500 or only B for $100.

	Product 1	Product 2	Product 3
Feature A	X		X
Feature B		X	X
Price	$ 200	$ 100	$ 500

Figure 2: Simplified FOCUS table in which each of the products supports one or both features. The high price of product 3 is because it has additional features not important to the user and not shown here.

Test Procedure

In the test session each subject received a brief demonstration of FOCUS. Then they had to perform a short warm-up task with a product table that was unrelated to the later task. After this, the subjects used FOCUS to select an appropriate travel insurance for a specified trip. The product table contained 32 products with 29 features in 3 main groups. Of these features, 18 had simple yes/no values. The remaining 11 features were primarily numerical descriptions of insurance coverage limitations.

During the task, the sequence of selection steps was manually recorded. Help was given to anyone who had questions concerning the operation of the tool and the meaning of product features (i.e. insurance services).

Once a product had been selected, the subject was asked to rate the importance of each of the product features on a separate sheet of paper. This rating was then used to assess whether participants selected the product that optimally matched their preferences.

RESULTS AND DISCUSSION

None of the subjects relied exclusively on a sequential selection strategy, but most used sequential selection as a micro-strategy during part of their problem-solving process. Upon reaching a desired feature in the list, they selected it without considering that there might be other product features further down the list that they would have rated more important. If this problem was not detected before the next selection was made, users were led into dead-end situations from which many participants needed help to back out of. The three suboptimal solutions can be directly attributed to sequential selection. Effective users avoided getting into problematic situations by using a combination of the following strategies:

• Exploring before selecting: They initially took more time to explore the complete set of features. In particular, these users investigated the price range of the available products and the value ranges of more complex features that were not described by simple yes/no options.

• Important features first: Effective users first decided on the relative importance of each feature and then they made their selections according to this order.

• Price-sensitive selection: Effective users investigated the effects of feature selection on the price. That is, after selecting a feature, they checked the price of the cheapest remaining product. An alternative, but potentially less effective strategy was to decide first on the maximum price that one is willing to pay and to exclude the more expensive products from the start.

In conclusion, our study showed that some users do have difficulty working with the IRIT technique, but that there are strategies to avoid these problems. We are planning to explore different means to enhance and facilitate the use of effective product selection strategies by casual users. In particular, we want to investigate strategy instruction, demonstration and training of additional FOCUS features, as well as supply special system support.

ACKNOWLEDGMENTS

REFERENCES

2. Rao R, Card S: The Table Lens: Merging Graphical and Symbolic Representations in an Interactive Focus+ Context Visualization for Tabular Information. In Proceedings of CHI '94, Boston, 1994, ACM Press, 318-322.

3. Spenke M, Beilken C, Berlage T: FOCUS: The Interactive Table for Product Comparison and Selection. In Proceedings of UIST '96, Seattle, 1996, ACM Press, 41-50.