The log rank test relies on several assumptions: 1. Independent Censoring: The reasons for censoring (loss to follow-up, etc.) should be unrelated to the likelihood of the event occurring. 2. Proportional Hazards: The ratio of the hazard functions (risk of the event happening) for the groups being compared should be constant over time. 3. Non-informative Censoring: Censoring should not provide any information about the survival prospects of the patients.