There is weak evidence human cancer risk might increase as a result of occupational exposure to large amounts of glyphosate, such as agricultural work, but no good evidence of such a risk from home use, such as in domestic gardening. According to a systematic review and meta-analysis published in 2016, when weak statistical associations with cancer have been found, such observations have been attributed to bias and confounding in correlational studies due to workers often being exposed to other known carcinogens. The review reported that studies that show an effect between glyphosate use and non-Hodgkin lymphoma have been criticized for not assessing these factors, underlying quality of studies being reviewed, or whether the relationship is causal rather than only correlational. Writing for the Natural Resources Defense Council environmental advocacy group, Jennifer Sass criticized the influence exerted by Monsanto on research about glyphosate safety, and noted that the review was funded by Monsanto.