Frank Kleibergen is a leader in the field of econometric methods that remain reliable in case of so-called 'weak instruments'. In economics, it is often impossible to directly determine the effect of one variable on another. This occurs since both are influenced by an unobserved background variable, such as when establishing the effect of the education spell on income. Both variables are influenced by intelligence, which is typically not observed. It is therefore common to determine the effect using a third set of variables, i.e. the instruments. These instruments are called weak when their explanatory power is small. When this occurs, traditional econometric methods become spurious and can show support for a relationship which does not exist. Since such weak instruments are common, econometric methods that remain reliable in such instances are important for applied research.

Kleibergen has contributed some of the initial econometric methods that are robust to weak instruments. He has published them in a number of articles in Econometrica, the most prestigious journal in economics, with a large number of citations. Kleibergen has also published extensively in other prominent journals such as the Journal of Econometrics, Journal of Business and Economic Statistics, Econometric Theory, Journal of Applied Econometrics and the Review of Economics and Statistics.

Kleibergen has been full professor of Economics at Brown University, an Ivy League university, since 2003. Previously, he was employed at the UvA as a postdoc and associate professor. Kleibergen has received various research grants, including one from the Innovational Research Incentives Scheme of the Netherlands Organisation for Scientific Research (NWO).