Argumentation incorporated into class discussions can improve students' problem solving skills and enhance their epistemic and conceptual understanding. Research indicates students sometimes need scaffolding such as goal instructions to improve their argumentation skills. This study examined the effectiveness of different types of goal instructions on participants' argumentation achievement. In particular, the study compared the effects of minimal, moderate, substantial, and no goal instructions in asynchronous online discussions on participants' argumentation achievement, as measured by development, balance, and explanatory discourse scores. The study also tried to understand participants' experiences of the goal instructions by comparing the differences in emergent themes across goal instructions groups. Ninety-seven undergraduate students participated in three debates and posted responses to an open-ended qualitative question over a three-week period. The study found significant differences in the balance scores between minimal, moderate, and substantial goal instructions and no goal instructions, indicating that goal instructions are effective in facilitating responses that consider both sides of an issue. In particular, findings suggested that goal instructions with any level of specificity are more effective in creating balance in argumentation than no goal instructions and that minimal goal instructions are more effective than moderate and substantial goal instructions in encouraging participants to present both sides of an issue. While the study did not find significant differences in explanatory discourse scores, the differences were close enough to significance to suggest that goal instructions did have some positive effect on helping participants consider other people's perspectives in a constructive way and build on each other's ideas. Quantitative analysis of codes across goal instructions groups revealed participants who received limited instructions focused their discussions on the environment itself while participants who received extended instructions focused their discussions on the impact that debates had on them. Therefore, it is likely that more extended instructions made an impact on encouraging participants to think about their views and consider other people's perspectives. The study did not find significant differences in development scores or differences in participants' perceptions across goal instructions groups. However, there are indicators that suggest that participants might have dismissed many aspects of moderate and substantial goal instructions, and additional research is needed to confirm these conclusions. Additional research on goal instructions using different methods for evaluating quality of argumentation is also needed to confirm the results of this study. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]