Manufacturing is intensive in the use of reproducible factors and exhibits greater technological dynamism than primary production. As such its growth is central to long-run development in low-income countries. Sub-Saharan African countries are latecomers to industrialization, and barriers to manufacturing growth, including those that limit trade, have been slow to come down. What factors contribute most to increases in output and productivity growth in their manufacturing sectors? Recent trade-IO theory suggests that trade liberalization should raise average total factor productivity (TFP) among manufacturing firms (Melitz 2003), but these predictions are conditional on maintained assumptions about the nature of industries, factor markets and trade patterns that may be less suitable in a developing-country setting. Manufacturing industries and firms are heterogeneous, so this analysis demands disaggregated data. We use firm-level data from the World Bank’s Regional Program on Enterprise Development (RPED) covering Ghana, Kenya, Nigeria, and Tanzania, 1991-2003. Among other things, the data distinguish exports by destination (Africa and the rest of the world), which is important due to the spread of intra-Africa regional trade agreements (RTAs). Econometric results confirm well-known relationships, for example a positive association between export intensity and TFP. However, we also find the destination of exports to be important. Export firms are more productive but have experienced declining TFP growth, and this has occurred at different rates depending on the country and the export market addressed. We show that these differentials are consistent with predictions from a modified statement of the Melitz model. The TFP results add a new dimension to controversies over the development implications of trade liberalization and the promotion of intra-Africa RTAs.

制造业对可再生要素的使用是集约化的，比初级生产表现出更大的技术活力。因此，其增长对低收入国家的长期发展至关重要。撒哈拉以南非洲国家是工业化的后来者，制造业增长的障碍，包括那些限制贸易的障碍，一直在缓慢地消除。哪些因素对制造业的产出增长和生产率增长贡献最大?最近的贸易io理论表明，贸易自由化应该提高制造业企业的平均全要素生产率(TFP) (Melitz 2003)，但这些预测是基于对产业、要素市场和贸易模式的假设，这些假设可能不太适合发展中国家的环境。制造业和企业是异质的，因此这种分析需要分类的数据。我们使用了世界银行1991-2003年加纳、肯尼亚、尼日利亚和坦桑尼亚地区企业发展项目(RPED)的企业层面数据。除其他外，这些数据按目的地(非洲和世界其他地区)区分出口，由于非洲内部区域贸易协定(RTAs)的普及，这一点很重要。计量经济学结果证实了众所周知的关系，例如出口强度与全要素生产率之间存在正相关关系。然而，我们也发现出口目的地也很重要。出口公司生产率更高，但全要素生产率增长下降，而且随国家和所处理的出口市场而不同。我们表明，这些差异是一致的预测，从修改声明的Melitz模型。全要素计划的结果使关于贸易自由化和促进非洲内部区域贸易协定对发展的影响的争论增加了一个新的层面。