Causal inference is a multidisciplinary field focused on understanding cause and effect, the basis of many research topics in health and social care. The role of randomized clinical trials in investigating treatment effects is well established, but causal inference in observational research is experiencing a surge in popularity and appreciation by regulatory authorities. Interest in it is reflected in the growing number of publications using causal inference methods, including Research Methods and BMJ Original Methods Research (RMR). Three RMR articles recently published in The BMJ highlight trends and clarify important aspects for the design and interpretation of causal inference in health research. The first two articles assist in the design and analysis of causal inference studies using observational data with a target trials emulation framework. Cashin and colleagues provide consensus-based guidelines for reporting such studies.