买方势力空间溢出效应研究--基于空间杜宾模型

A Study on the Spatial Spillover Effect of Buyer Power--Based on Spatial Durbin Model

企业研发投入不仅受自身属性和横向市场行业属性因素影响,纵向市场中相邻行业不断增强的买方势力也成为重要影响因素。基于中国经济与社会发展统计数据库各统计年鉴2001年至2015年制药行业和医疗行业数据,分析医疗行业买方势力对制药行业研发投入的影响。当以新产品销售收入占销售收入比值测量研发投入时,卖方销售收入同时来自本地和其他地区买方市场,即纵向视角下买方势力对制药行业绩效的影响存在溢出效应,需考虑特殊多对多交互作用。通过构建卖方31个制药企业与买方31个医疗企业纵向关系,利用空间杜宾模型分析买方势力对制药行业研发投入的空间溢出效应。研究结果表明,地区制药行业研发投入呈现高值与高值、低值与低值空间集聚特征。以地区医院总个数表征买方势力、制药企业总数表征卖方势力时,反距离空间权重矩阵与经济距离空间权重矩阵回归结果仅存在较小差异;直接效应和间接效应均为负,表明本地买方势力不仅抑制本地制药行业的研发投入,还通过空间溢出效应抑制其他地区的研发投入,但空间溢出效应不明显。直接效应系数的绝对值显著大于间接效应系数的绝对值,表明同一地区纵向产业链市场主体交易关系和经济联系更密切,下游行业对供应商行为纵向约束力更强。上下游行业之间较为对等的市场势力有利于研发活动的开展,卖方相对市场势力较强或较弱均降低研发激励,深刻体现卖方抗衡势力作用。制药行业规模、资产专用性、企业规模、市场需求增长率与研发投入负相关,技术创新落后于产业规模和企业规模扩张步伐,产业量扩张显著,但质的提高不大;政府规制、人均GDP、销售利润率、产品差异性与研发投入正相关。以地区医院总个数表征买方势力、制药行业销售收入表征卖方势力进行模型扩展时,也证明上述结论具有稳健性。把空间计量模型引入纵向关系实证分析,拓展了纵向研究方法。

The R&D investment of enterprises is not only influenced by the attributes of themselves and factors of industry attribute in horizontal markets,but also the increasing buyer power from adjacent industries in vertical markets has become an important influencing factor.Based on the data of pharmaceutical manufacturing industry and medical industry from 2001 to 2015 collected from different statistical yearbooks of China’s economic and social development statistics,we try to analyze the influence of buyer power in medical industry on R&D investment for pharmaceutical industry.When R&D investment is measured by the ratio of new product sales revenue to sales revenue,sales revenue of sellers comes from both local and the rest regions of downstream buyer markets,namely,there is a spillover effect existing in the influence of buyer power on upstream manufacturers’conduct and performance from the vertical perspective,special considerations on many-to-many interactions need to be taken into account.By setting up the vertical relationships between 31 pharmaceutical enterprises of sellers multiplied by 31 medical enterprises of buyers,we utilize spatial durbin model to analyze the spatial spillover effect of buyer power on manufacturers’R&D investment.The empirical results show that R&D investment of regional pharmaceutical industry presents the characteristics of high(lower)value and high(lower)value for spatial agglomeration.When buyer power is characterized by the total number of regional hospitals,seller power is characterized by the total number of regional pharmaceutical enterprises,yet given the regression results of inverse distance matrix and economic distance matrix,there are only minor differences.The direct effects and indirect effects are both negative,indicating that the local buyer power not only restraints the R&D investment of local pharmaceutical industry,but also restraints the R&D investment for the rest regions through spatial spillover effect.However,the spatial spillover effect is not much significant.The absolute value of direct effects is significantly greater than that of indirect effects,which shows that the transaction relationship and economic connection of market entities of vertical industry chain in the same region are closer,while the downstream industry has stronger vertical binding power on suppliers’behavior.The relatively equal market power between upstream and downstream industries is conducive to the launch of R&D activities,and the relatively strong or weak market power of sellers reduces both R&D incentives,the role of seller countervailing power is deeply reflected.The scale of pharmaceutical industry,asset specificity,enterprise size and market demand growth rate are negatively related to R&D investment.Technological innovation lags behind the pace of industrial scale and enterprise size expansion,the expansion of industrial volume is remarkable,but the qualitative improvements are not much.Government regulation,per capita GDP,sales profit margins and product differentiation are positively related to R&D investment.When the total number of regional hospitals and the sales revenue of the pharmaceutical industry are used to measure the expansion model of buyer power and seller power respectively,it also proves the robustness of the conclusion above-down.This study innovatively expands the vertical research method.That is,the spatial econometric model is introduced into the empirical analysis of vertical relationships.