How persistent is industry specialization over time in industrialized countries?

I use the 1994 OECD Structural Analysis database, which provides statistics on output for 33 manufacturing industries in II OECD countries over the pe riod 1970 to 1993. I find that in 1970, these countries tended to specializ e manufacturing production in very different industries and that most count ries retained their specialization between 1970 and 1993. I conclude that t he general stability in industries of specialization over time lends suppor t to the increasing internal returns to scale models and tends to contradic t the standard factor-price equalization models. The results of this paper also suggest that increasing internal returns to scale and learning-by-doin g may serve as a complement to potent protection and other forms of intelle ctual property rights.