Abstract:    The literature on standards emphasizes that influencing technological standardization have dramatic repercussions for firm competitiveness and performance. Rapid technological change and complex product design in high-tech industries make it less likely for firms to formulate and promote industry standards independently, firms must engage in alliances to gather external technology and expand installed user base to improve their competitiveness. Although related literature contributes an understanding of standard-setting alliance formation and operation, the question remains of why allied-firms show persistent differences in their capabilities to influence technological standardization. The resource-based view states that sustained competitive advantage draws from firms′ resources and capabilities which are valuable and non-substitutable, and alliances can contribute to firms′ competitiveness by acting as important external resource pools. The value of external resources derives from diversity which can offer multiple solutions. A diverse alliance portfolio can provide a firm with access to nonredundant external knowledge and pervasive support, helping the firm accumulate sufficient knowledge and social capital for technical proposals. Thus, alliance portfolio diversity which emphasizes the composition of alliance partners, is important to explain the role of standardization collaboration in standard-setting. Inter-firm knowledge sharing is far more difficult than intra-firm knowledge sharing. Generally, the resources from alliances cannot be directly transformed into firms′ advantages, firms need to maintain certain degree of tie strength to influence partner firms′ effort in cooperation and their willingness of knowledge exchange. Therefore, following the contingency approach to explicit consider the role of alliance tie strength would be useful to understand the relationship between alliance portfolio diversity and the firm technological standardization capability. 
   The current study, built on a resource-based view and social capital theory, sheds light on standard-setting alliance portfolio diversity and its impact on firm technological standardization capability. We contend that there exist two different types of capabilities to influence technological standardization: technological standardization dominant capability and following capability. We put forth that the degree of alliance portfolio diversity may bring different advantages and disadvantages to firms focusing on different types of capabilities. The potential for making full use of alliance portfolio diversity depends on the tie strength that a firm maintains with their partners, which acts as catalyst or inhibitor for firm particular types of capabilities to influence standardization. We empirically test our hypotheses using an unbalanced panel data of 170 Chinese vehicle manufacturers for the period of 1999 to 2013. Data collected include all formal technical standards (Chinese Classification for Standards code T) in the auto industry and firm level yearly information on firm age, enterprise property, patents and standards set by each firm. We use the co-draft standards which are identified as cooperatively developed by two or more organizations (including firms, universities, research institutes and government institutes) to build the standard-setting alliance portfolios. A negative binomial regression is adopted to estimate the parameters, as it can better deal with count variables and allow for over dispersion of the variance in the dependent variables. When accommodating an unbalanced data set, a random-effects model is attractive because it takes advantage of between-unit variation but allows for different intercepts. Therefore, we use a random-effects negative binomial model to estimate the parameters.
   Mixed results are found regarding alliance portfolio diversity and our two types of technological standardization capabilities. Firstly, alliance portfolio diversity has a U-shaped relationship with firm technological standardization dominant capability. Highly diversified alliance portfolios can offer firms opportunities to acquire and integrate external resources required by standard-setting, being beneficial for firms to coordinate the industry value chain and to dominate the standardization. Homogeneous alliance portfolios also can effectively gather market power and activate competition among partners, thus offering firms′ bargaining power and strengthened dominant capability in standardization process. Secondly, alliance portfolio diversity shows a strong inverted U-shaped relationship with firm technological standardization following capability. Moderate level of alliance portfolio diversity can provide a certain degree of decision-making flexibility, and abundant opportunities of standard-setting collaboration, being helpful for firms to follow other standard-setting leaders to influence industry standardization. But firms′ technological standardization following capability also suffer when their alliance portfolios are highly diversified, as they may face problems of invalid knowledge integration, excessive cost of relationship management and scattered distribution of resources. Thirdly, alliance tie strength steepens both upward and downward slopes of the U-shaped relationship between alliance portfolio diversity and firm technological standardization dominant capability. Firms who keep stronger ties with alliance partners will suffer more in terms of developing technological standardization dominant capability, from increasing alliance portfolio diversity from a low to moderate level. But these firms also can benefit more in terms of developing technological standardization dominant capability, from increasing alliance portfolio diversity from a moderate to high level. Fourthly, alliance tie strength moderates the relationship between alliance portfolio diversity and the firm technological standardization following capability in such a way that both the upward and downward slopes of the inverted U-shaped relationship will become steeper at a high level of alliance tie strength. When alliance portfolio diversity increases from a low to moderate degree, firms who keep stronger ties with alliance partners will benefit more from standardization collaborations to develop technological standardization following capability as compare to a low level. When alliance portfolio diversity is excessive, a high level of tie strength will amplify the negative effect of alliance portfolio diversity on firm technological standardization following capability. Overall, these findings can provide valuable guidance for firms′ standardization and innovation activities. To develop technological standardization dominant capability, firms should maintain many weak ties with same type of partners or strong ties with multi-types of partners; To enhance technological standardization following capability, firms would better keep moderate level of alliance portfolio diversity and maintain relative strong ties with partners. The two types of technological standardization capabilities have conflicting requirements for the composition and relation features of alliance portfolio, firms should choose a relative optimal arrangement for alliance portfolios to balance the two types of capability development.

Key words: alliance portfolio diversity, tie strength, technological standardization dominant capability, technological standardization following capability