The research aim of the second project is similar to that of the first project, but the focus is now on gaining an insight into what characteristics of an argument in support of a desirability claim determine its quality. To reach this aim, three research questions similar to those of the first project are formulated and addressed using similar research methods. The major differences between the projects lie in the different types of argument that are used to support the different types of claim (research question 1 and 2) and the main dependent variable in the experiment (perceived desirability instead of perceived probability). 1. What criteria have been developed in argumentation theo theory to evaluate the quality of arguments in support of a desirability claim? A literature search will be conducted to identify the types of argument that can be employed to support a desirability claim. Some of these types can be used to support desirability claims only (e.g., rule-based argumentation (Schellens, 1985), normative Schemata (Kienpointner, 1992); argument from waste (Walton, 1996)), others can be used more broadly (e.g., arguments based on authority). Next, a systematic framework of evaluation questions to assess the quality of the different types of argument is developed. 2. What criteria do lay people use to evaluate the quality of a of arguments in support of a desirability claim? Again, three to four focus groups will be conducted to (1) make an inventory of the types of argument that lay people use to support a desirability claim and (2) the criteria they use to distinguish strong from weak arguments. As a preparation for the focus group, participants are given claims such as â increasing the time spent on mathematics in high school is desirable and asked to come up with strong and weak arguments in support of this claim. 3. Are arguments that conform to the lay criteria for argu argument quality more persuasive than arguments that do not conform these criteria for participants who scrutinize the arguments? An experiment is conducted in which desirability claims are supported by (1) different types of argument that (2) are manipulated with regard to the extent they conform to the criteria for strong arguments. The main dependent variable is the perceived desirability of the event measured on a five-point Likert scale ranging from very undesirable to very desirable. Again, a within-participant latin square design is used to enable drawing generalizations over participants as well as (1) types of argument and (2) arguments that do or do not conform to the criteria for strong arguments. A similar procedure as in project 1 is used to ensure that participants pay close attention to the arguments.