This document summarizes a survey of data quality and validation mechanisms used in citizen science projects. The survey found that most projects use expert review and that projects use an average of 2.5 validation methods, often in combination. Larger projects and those with more funding tend to use fewer validation methods that require more human resources. Common validation methods included expert review, photo submissions, paper data sheets, and replication by multiple participants. Future work should focus on validation of data analysis methods and developing tools to help projects plan quality assurance procedures.