Economists, using growth models, have traditionally explained output and economic growth by the amount of capital and labour employed and the level of technology engaged. Policies to promote economic growth have consequently emphasized investment and savings, mobility of capital and labour and the level of technology. These models have been less than satisfactory since large unexplained residuals normally remain. (Regional growth models are variations of the macroeconomic models with location taken into account to explain differences in growth rates between regions. Policy prescriptions for regional development focus on ameliorating spatial disadvantage through infrastructure improvements.) Local development can help explain the residuals which remain unexplained in the macroeconomic growth models.