David Sargan is a notable figure in the field of statistics and econometrics. He is best known for his contributions to the development of statistical methods, particularly in the context of econometric modeling. His work has influenced various applications in economics and social sciences. Sargan is also recognized for the Sargan test, a statistical test used to assess the validity of instruments in instrumental variable estimation. This test helps researchers determine whether their chosen instruments are appropriate, ensuring more reliable results in econometric analyses.