Trade Liberalization, Wages, and Employment in Developing Countries: The Role of Political Economy and the Informal Sector

关于贸易自由化利弊的公开辩论往往集中在贸易改革如何影响劳动力市场的问题上。但是，尽管这个问题在公共政策中占有突出地位，迄今为止的实证研究还没有提供关于贸易自由化对就业和工资影响的确凿证据。这反映了与该领域的实证工作有关的两个主要困难。第一个是衡量问题：近年来，发达国家的贸易保护采取了非关税壁垒的形式，这些壁垒本身就很难（如果不是不可能的话）衡量。第二个限制是，贸易保护的政治经济学虽然在贸易理论和进口渗透的实证研究方面取得了进展，但在贸易改革对工资影响的研究中仍然是次要问题。本研究利用哥伦比亚1985年至1994年的贸易自由化，在这些问题上取得进展。哥伦比亚的贸易改革主要包括多次关税削减，不仅大幅降低了平均关税，而且影响了各行业的保护结构。专注于关税的优势在于，它们都可以很好地衡量，而且——与NTB的衡量标准相反——可以在不同时期进行比较。本项目的基本思路是将不同行业的关税变化与每个行业的工资和就业联系起来，以调查贸易自由化是否会导致关税降幅较大的部门的工资降低，以及/或部门间的劳动力再分配。所采用的框架明确说明了贸易保护的政治经济学。对行业层面调整的关注不同于以往的文献，后者关注的是贸易政策变化对特定工人特征回报的影响（最突出的是技能和教育回报）。这些研究集中在长期贸易改革的后果，当工人的行业隶属关系不重要。然而，在中短期贸易模型中，行业从属关系对于预测贸易改革的影响至关重要。这些模型似乎特别适用于发展中经济体（如哥伦比亚），因为这些经济体的劳动力市场僵化阻碍了劳动力在各个部门之间的流动。由于哥伦比亚象许多其他发展中国家一样，其特点是有一个很大的非正式部门，因此这项研究的很大一部分专门用于分析这个部门的调整过程。该研究特别审查了贸易自由化是否促成了1990年代所记录的劳动力非正式性的增加，以及正式部门和非正式部门的工资和就业是否受到不同的影响。这项分析利用了哥伦比亚国家规划部关于工业关税的资料和1984-1998年期间全国住户调查的详细工人水平数据（其中包括关于工作场所特点和非正式性的资料）。虽然这项工作没有试图对收入不平等进行一般分析，但它对当前关于贸易改革对工资差异影响的辩论有影响。这个问题在以严重不平等为特点的发展中国家尤为重要。除了有充分证据证明的全经济技能溢价的增加之外，这项工作还发现了差距的一个来源：发展中国家的关税削减在初始工资较低的部门更大，雇用了更多比例的低技能工人，这些部门的行业工资下降将不成比例地影响这些工人。同样，贸易自由化导致的非正规部门扩张，通常与较低的工资和零福利有关，可能会加剧不平等。虽然这些考虑并不意味着贸易自由化是不可取的，但它们指出有必要查明在短期和中期可能需要调整援助的部门和工人群体。更一般地说，对贸易自由化后的调整过程的分析可能有助于理解和解决我们在实践中经常观察到的特定群体对贸易改革的抵制。

The public debate on the merits and perils of trade liberalization often centers on the question of how trade reforms affect labor markets. But despite the prominence of this question in public policy, empirical research to date has offered no conclusive evidence on the effects of trade liberalization on employment and wages. This reflects two main difficulties associated with empirical work in the area. The first one is a measurement issue: in recent years, trade protection in developed countries has taken the form of non-tariff barriers that are inherently hard, if not impossible, to measure. A second limitation is that the political economy of trade protection, while having made inroads in trade theory and empirical studies of import penetration, has remained a second-order concern in studies of the effects of trade reform on wages. This study makes progress on these issues by exploiting the Colombian trade liberalization between 1985 and 1994. The Colombian trade reforms consisted primarily of multiple tariff reduction episodes that not only drastically lowered the average tariff, but also affected the structure of protection across industries. The advantage of focusing on tariffs is that they are both well measured, and -- contrary to NTB measures -- comparable across time. The basic idea in this project is to link tariff changes, which varied substantially across industries, to wages and employment in each industry, in order to investigate whether trade liberalization leads to lower wages in sectors that experienced larger tariff reductions, and/or labor reallocation across sectors. The adopted framework explicitly accounts for the political economy of trade protection. The focus on industry-level adjustment differs from the previous literature that has concentrated on the effects of trade policy changes on the returns to particular worker characteristics (most prominently, returns to skill and education). These studies focus on the consequences of trade reforms in the long run, when worker industry affiliation does not matter. However, industry affiliation is crucial in predicting the impact of trade reforms in short- and medium-run models of trade. These models seem particularly relevant in developing economies (like Colombia) where labor market rigidities obstruct labor mobility across sectors. Because Colombia, like many other developing countries, is characterized by a large informal sector, a significant part of this research is devoted to the analysis of the adjustment process in this sector. In particular, the study examines whether trade liberalization has contributed to the increase in informality of the workforce documented in the 1990's, and whether wages and employment were affected differentially in the formal and the informal sectors. The analysis utilizes information on industry tariffs from the Colombian Department of National Planning and detailed worker level data from the National Household Survey (that include information on workplace characteristics and informality) over the period 1984-1998. While this work does not attempt a general analysis of income inequality, it has implications for the current debate on the effects of trade reform on wage dispersion. The question is of particular importance in developing countries that are characterized by substantial inequalities. The work identifies a source of disparity beyond the well-documented increase in the economy-wide skill premium: to the extent that tariff reductions in developing countries are larger in sectors with lower initial wages, employing a larger fraction of less-skilled workers, a decrease in the industry wages of these sectors will affect such workers disproportionately. Similarly, a trade liberalization-induced expansion of the informal sector, which is typically associated with lower wages and zero benefits, may increase inequality. While such considerations do not imply that trade liberalization is undesirable, they point to the need to identify sectors and worker groups that may need adjustment assistance in the short and medium run. More generally, an analysis of the adjustment process following trade liberalization may help understand and address the resistance of particular groups to trade reforms we often observed in practice.