Medication adherence is the process by which patients take their medications as prescribed. Medication nonadherence is a major problem, resulting in over 100,000 preventable deaths and more than 100 billion dollars in preventable healthcare costs every year in the United States. Many fundamental and clinically important questions surround nonadherence, including (1) why some drugs are "forgiving," in that they maintain efficacy despite nonadherence (missed doses, late doses, etc.) whereas other drugs are decidedly not forgiving, and (2) how the deleterious effects of nonadherence can be mitigated by designing robust dosing regimens and identifying remedial protocols for whether patients should skip or take late doses of medication. This project uses mathematical modeling and analysis to answer these questions. This project has strong potential to improve societal well-being via improved pharmacotherapy outcomes. These improvements will arise both from nonadherence mitigation for existing medications and a new quantitative understanding of drug forgiveness allowing for identification and design of robust medications. This project will develop the STEM workforce through training junior researchers. Medication nonadherence is challenging to study because (a) clinical trials that force patients to skip doses may be unethical, (b) nonadherence is erratic (i.e. patients do not miss doses in regular, deterministic patterns), and (c) there are many competing factors to consider (a