Hello, I am using panel data with N= 37 (countries) and T= 31 (1990 to 2020). After reading about literature of dynamic panel methods, I found that when T is small and N is large, it's better to use System GMM. And with large T and small N it's better to use PMG-ARDL My questions are how small should be T and N to choose between the two methods ? And in my case (N= 37 ; T= 31) which method is more suitable, GMM or PMG ? NB : Using the PMG, I found more significant results than GMM, in short run. Thank you