the moduli as would be required in the usual chiral field formulation of the effective supergravity coming from string theory. The resolution in terms of the linear and chiral multiplet duality was discussed in [@Derendinger:1991hq][@Binetruy:2000zx] (BGG) and is reviewed in section two, where we also point out that the argument fails when the modulus in question has a non-linear superpotential term in the relevant chiral superfield. In the next section we review the arguments of Kaplunovsky and Louis which compared their field theoretic formula for the gauge coupling function with the corresponding string theory calculation. It should be stressed that this only involved momentum scales below the string scale (as we will make clear below). By contrast the work of references [@Conlon:2009xf; @Conlon:2009kt; @Conlon:2010ji], as well as the earlier work of [@Bachas:1998kr; @Antoniadis:1998ax; @Antoniadis:1999ge] in connection with low scale strings, is essentially based on using the effective field theory and background string theory approaches well above the string scale. The point is that in identifying the infra-red region of the string theory integrand the upper (UV) cut off is taken beyond the string scale. This is essentially the meaning of taking the infra-red region of the one-loop string integral all 