Individual participant data

Individual participant data (also known as individual patient data, often abbreviated IPD) is a type of meta-analysis in which data is collected line-by-line from each patient in the studies being analyzed. Due to the high level of precision and consistency this approach allows for (which in turn makes it easier for researchers to minimize heterogeneity), it is considered the gold standard of meta-analyses. The other type of meta-analysis relies not on IPD but on aggregate data (AD). Although the AD approach is more traditional, in the 21st century, meta-analyses conducted with IPD (also known as IPD meta-analyses) have become increasingly popular. IPD meta-analyses tend to be for large-scale and international projects, and they are less limited than AD meta-analyses in terms of the availability and quality of data they can use. The International Committee of Medical Journal Editors (ICMJE) has stated that sharing of deidentified individual participant data is an ethical obligation.