Productivity Growth and Product Variety : Gains from Imitation and Education

Addison, Douglas M.

World Bank, Washington, DC

关键词: AVERAGE GROWTH;    AVERAGE GROWTH RATE;    AVERAGE RATE;    CAPITAL GOODS;    CAPITAL GROWTH;   

DOI  :  10.1596/1813-9450-3023
RP-ID  :  WPS3023

学科分类：社会科学、人文和艺术（综合）

来源: World Bank Open Knowledge Repository

【 摘 要 】

Is there a correlation betweenproductivity and product variety? Certainly it appears thatthe rich countries are more productive and have more productvariety than the poor nations. In fact, the relationship isquite strong when measured in levels. Does this samecorrelation hold up when measured in growth rates? If so,can poor countries imitate the success of the rich? Addisonprovides theoretical and empirical reasons to believe theanswer to both questions is yes. Recent economic theorysuggests that rising variety in factor inputs can help avoiddiminishing marginal returns. Product variety can alsosustain learning-by-doing which would otherwise be exhaustedin a fixed number of products. Finally, invention orimitation adds to the stock of non-rival knowledge. Therehave been only two previous empirical tests of thecorrelation between growth in product variety andproductivity growth. Both were affirmative but neitherexamined a wide range of developing countries and neitherlooked deeper to test what might drive product variety. Thisresearch is based on a cross-country sample of 29 countries(13 rich and 16 poor). The data display a statisticallysignificant and positive relationship between growth inproduct variety and productivity growth when condition onother variables such as research and development (R&D)employment, macroeconomic stability, and domestic security.These results are robust to the addition and subtraction ofvarious explanatory variables but fragile with respect to aninfluential data point for Venezuela. Industrial nationstend to generate most of their productivity gains throughR&D employment in a stable environment that results inbetter production processes and product quality. Incontrast, the largest source of productivity growth indeveloping countries is product variety imitation whileinstability takes away from productivity. Addison testsvarious explanations for growth in variety. The results showthat nations furthest from the frontier of observablevariety tend to imitate fastest, with the ability to imitatebeing improved by educational attainment and by productivitygains. This could be a source of hope for small, lessdeveloped nations. Growth in market size was not correlatedwith growth in variety, though this may be due to a rathershort sample period of only eight years. In addition to theempirical testing, Addison also contributes to a generaldiscussion of measurement concepts and measurement issuesrelated to product variety and sets out an agenda forfurther research.