This article extends the lsdv bias-corrected estimator in (bun and carree, 2005 bun, m. And carree, m. 2005. Bias-corrected estimation in dynamic panel data models. Journal of business and economic statistics, 23: 200–9. [taylor & francis online], [web of science ®], , [google scholar]) to unbalanced panels and discusses the analytic method of obtaining the solution. Using a monte carlo approach the article compares the performance of this estimator with three other available techniques for dynamic panel data models. Simulation reveals that lsdv-bc estimator is a good choice except for samples with small t, where it may be unpractical. The methodology is applied to examine the impact of internal and external r&d on labour productivity in an unbalanced panel of innovating firms.