@article {karim2016comparison, title = {Comparison of Statistical Approaches for Dealing With Immortal Time Bias in Drug Effectiveness Studies}, journal = {American Journal of Epidemiology}, year = {2016}, pages = {kwv445}, publisher = {Oxford University Press}, doi = {10.1093/aje/kwv445}, author = {Karim, Mohammad Ehsanul and Gustafson, Paul and Petkau, John and Tremlett, Helen} }