This dissertation explored how effectively first-year writing (FYW) evaluated and selected sources for their researched writing assignments. Though students were taught how to access sources from the library and offered sources on the course management system, most often they obtained sources via the open internet. As mis- and disinformation proliferates online, it is important that students effectively discern credible and accurate information from non-credible sources. As a form of action research, I collected data from student participants in my FYW classes during normal class procedures. Several instruments were used to collect data before and after students learned about the presence misinformation, how it may dupe readers, and the lateral reading strategy of checking source credibility. This dissertation explored the following research questions, which yielded the associated key findings. Research Question 1: What is the impact of a lateral reading intervention on students' ability to evaluate source credibility and select sources for research-based writing assignments? Key findings included: FYW students improved their source evaluation skills after the lateral reading teaching intervention; FYW student participants evaluated sources based on more relevant criteria after the lateral reading teaching intervention; FYW students selected more credible sources for their researched writing assignments after the lateral reading teaching intervention. Research Question 2: What is the influence of students' misinformation concern on their source evaluation skills? Key findings included: before the teaching interventions, FYW student participants reported that they were moderately concerned about misinformation, more so while seeking information for academic pursuits than in general; there was a significant relationship between students' misinformation concern level and their ability to discern true vs. false news headlines. Research Question 3: What is the influence of students' misinformation susceptibility on their source evaluation skills? Key findings included: there was no significant relationship found between misinformation susceptibility and the ability to evaluate sources for credibility; FYW students were better able to discern true and false news headlines after learning about the presence of mis- and disinformation and their common strategies and motivations; participants who spent more time deliberating on discerning true vs. false headlines gained more accurate results. The teaching interventions employed in my study were effective in improving FYW student participants' abilities to evaluate source credibility and recognize misinformation. As a result, I recommend the FYW classroom as a setting for students to build on or learn the lateral reading strategy so that they may navigate through the information landscape and select more credible sources with more efficiency and certainty. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]