Comparative and single test object studies

These studies differ in the number of interfaces that are being tested. Single test object studies will cover only a single product, while comparative studies involve two or more products in order to compare them. Comparative studies may be run in order to determine which alternative of a product’s early design better reflects the user's expectations. The aim of this type of study is to either find a preferred candidate or identify the best aspects of either alternative which can then be used to drive the further design of the product. Comparative studies can also be used to determine how competing products measure up against each other.

Another aspect of comparative studies is whether all study participants will test all test objects (within-subjects) or whether each study participant only tests one of the test objects (between-subjects). Both have their advantages and disadvantages; fewer participants are required for a within-subject study, but the study duration is necessarily longer, while a between-subjects study eliminates anchoring bias (judging subsequent test objects by comparing them to the subjective baseline made after using the first one). 

Comparative studies and studies of a single test object are compatible with remote methodologies.