THE LESSON LEARNT FROM Childers. 1986. Assessment of the psychometric properties of an opinion leadership scale

In this paper, the author revised the King and Summers' (1970) scale for opinion leadership. As many researchers have found, they argued that the opinion leaders were more likely to be product innovators and high in consumer creativity; were more likely to be risk preference and non-dogmatism; and were full of personal knowledge in certain products.
However, by using the KS scale (7-point response), each Alpha of the opinion leaders' personality was low (about 0.66). By using the same scale, the author could barely get high correlation between the result of KS scale and that which again got from KS scale. Thus, the validity of KS scale was doubted.
To improve this point, they utilized a 5-point scale and modified some KS scales (under the item-to-total correlation, they deleted the inappropriate items), in Table 2. In the end, the Alpha increased and the correlation between opinion leadership with creativity and ownership of the product was confirmed.
Also, to test the validity of the revised scale, different users of cable television (different in their degree of adoption of cable TV services) were analyzed. And, they found that, under Turkey HSD test of means, the average opinion leadership scores for premium subscribers and basic-only subscribers were significantly greater than the score for the group that had refused to subscribe to cable TV. Thus, the people who are familiar to TV services will found high in opinion leadership.

THE LESSON LEARNT FROM Chan & Misra. 1990. Characteristics of the opinion leader: A new dimension

In this paper, the authors analyzed the characteristics of opinion leaders (or givers). Historically, the opinion leaders were considered as important part in new-product adoption and diffusion, and venture business. In their personality, they tend to be less dogmatic, more innovative, more venturesome, likely to be confident in their appraisal of the product category, and more socially active. By analyzing 262 students and using Stepwise discriminant analysis, they found that contrary to previous findings, risk preference, dogmatism, and exposure to print media were not found to be significant discriminating characteristics of opinion leaders. But the product familiarity, personal involvement, and public individuation were significant in distinguishing opinion leaders from nonleaders (p. 57). The relationship between public individuation and opinion leadership is reasonable (p. 54).

THE LESSON LEARNT FROM Elfring & Hulsink, 2003. Networks in entrepreneurship: The case of high-technology firms

In this paper, the authors, using the theory of contingency, argued how strong and weak ties influenced the performance of high-tech start-ups in releasing incremental and radical innovations. They demonstrated that although strong and weak ties are both beneficial to venture businesses in terms of opportunity recognition, resource assembling, and legitimacy; their value is different when facing with different innovation types.
Thus, they proposed that a mix of strong and weal ties are crucial to the high-tech start-ups.
Towards discovery of opportunity, they demonstrated that networks could provide not only source of information bur help entrepreneurs evaluate the opportunities and potential markets. Here, the weak ties could provide more new and broad information whereas strong ties could be of importance of helping evaluating opportunities in greater detail.
Towards securing resources, strong ties provided privileged rights to help gather venture capital and work-forces. Also at the circumstance of legitimacy, the strong ties contributed in convincing potential market and existing industry to believe the innovative products.
In the end, the authors proposed that

1. For pursuing incremental innovations, weak ties are more likely to discover opportunities.
2. For pursuing radical innovations, the mix of strong and weak ties are more likely to discover opportunities.
3. Strong ties enable trusted feedback and exchange of tacit knowledge on the nature of the opportunity.
4. For pursuing incremental and radical innovations, strong ties are more likely to help secure resources.
5. Strong ties enable the exchange of tacit knowledge in the development of resources.
6. For pursuing incremental innovations, strong ties help ventures gain more legitimacy.
7. For pursuing radical innovations, the mix of strong and weak ties are more likely to gain legitimacy (cognitive ones and socio-political ones).
8. Weak ties are more important for radical innovations, as endorsement by outsiders is important in gaining legitimacy.

THE LESSON LEARNT FROM Freeman, L. 1978. Centrality in social networks: Conceptual clarification

First introduced by Bavelas in 1948, the idea of centrality in human community has been recognized. The centrality was related to group efficiency in problem solving, perception of leadership, and the personal satisfaction of participants. And, before arguing centrality, the graph-theory is necessary, where the words: "adjacent, degree of point, path, cycle, connected, distance, geodesics" have their unique meaning. 

In the terms of point centrality, "a point that falls on the communication paths between other points exhibits a potential for control of their communication." And, a central position is one that is not dependent upon others as intermediaries or relayers of messages. Short distances mean fewer message transmissions, shorter times, and lower costs. Especially, concern with communication activity will suggest a degree-based measure, interest in control of communication requires a measure-based upon betweenness; and concern with either independence or efficiency leads to the choice of a measure based upon closeness. 

The LESSON LEARNT FROM Borgatti, S. 1995. Centrality and AIDS

"Centrality measures are commonly described as indices of prestige, prominence, importance, and power - the four Ps." There are usually four measures, which were developed by Freeman (1979) and Bonacich (1972), being used in network analysis: degree, closeness, betweenness, and eigenvector centrality. "Degree centrality may be defined as the number of ties that a given node has." When all else is equal, we could describe degree centrality as measuring the risk (or opportunity) of receiving whatever is flowing through the network. Furthermore, in eigenvector centrality, it was demonstrated that "it wasn't just how many people a person knew that counted, but how many people the people that they knew knew." That's to say, an actor that is connected to many actors who are themselves well-connected is assigned a high score, but an actor who is connected only to near isolates is not. "Closeness centrality may be defined as the total graph-theoretic distance of a given node from all other nodes." "Betweenness centrality is defined as the number of times that a node needs a given node to reach another node." Thus, also according to Granovetter's (1973) definition, actors with many weak ties are more important than others because removing those actors would do the most damage to transmission possibilities throughout the network.

THE LESSON LEARNT FROM Shane. 2000. Prior knowledge and the discovery of entrepreneurial opportunities

Here, the author followed the logic that entrepreneurial opportunity discovery is a function of the distribution of information in society. For the information asymmetry and different experience, people usually discover different opportunities in a given technological change.

Thus, through investigating eight different new venture businesses based on the invention of 3DP, the author showed that " (1) any given technological change will generate a range of entrepreneurial opportunities that are not obvious to all potential entrepreneurs;" (2) entrepreneurs can and will discover these opportunities without searching for them; and (3) any given entrepreneur will discover only those opportunities related to his or her prior knowledge (p. 449).

Different from Neoclassical equilibrium theories and Psychological theories of entrepreneurship where the fundamental attributes of people were considered to determine who becomes an entrepreneur, Austrian theories which the author clearly followed emphasized that the information about opportunity was crucial. As the result of this difference, the Austrian theories showed a different explanation of the discovery, exploitation, and organization of entrepreneurial opportunities: (1) they did not view the process of opportunity discovery as mechanical; (2) the possession of information leads to opportunity discovery; and (3) opportunity exploitation is endogenous to opportunity discovery.

Basing on the same technological invention, since "each person's idiosyncratic prior knowledge creates a 'knowledge corridor'," people would discovery and exploit the opportunity in different ways. First, their prior knowledge about markets will influence people's discovery of which markets to enter to exploit a new technology; second, their prior knowledge about how to serve markets will influence the discovery of how to use a new technology to serve a market; third, their prior knowledge of customer problems will influence the discovery of products and services to exploit a new technology. Namely, the prior knowledge people got from work places or education and from roles of user or supplier, moderates (1) the relationship between technological invention and opportunity recognition and (2) the relationship between recognized opportunity and the approach of exploiting it.

It is important to notice that neither a technological change nor the search of opportunities will directly lead to the opportunity discovery, people's prior knowledge in market and recognition helps discover the opportunities (p. 465). "A large amount of technological change might generate a small amount of economic output, because it generates a small number of entrepreneurial opportunities" (p. 466). None of the new venture businesses were started by the inventor of 3DP.

THE LESSON LEARNT FROM Casson & Wadeson. 2007. The discovery of opportunities: Extending the economic theory of the entrepreneur

The entrepreneurship is considered as the choice under conditions of scarcity and entrepreneurs were the people who specialized in making choices that require intensive use of judgement. In this paper, the authors demonstrated that an entrepreneurial opportunity is best conceived as a potentially profitable but hitherto unexploited project. The reason why people did not notice the project could be rooted in the costs of discovery, since the information is often costly for potential entrepreneurs to obtain.

Entrepreneurs are the people who believe they have lower information costs than other people, believe that they had better theories, and advantage in collecting and processing information. The ends pursued by entrepreneurs might be non-materialistic or purely financial rewards.

As the result of changes in the environment and the opportunity recognition stimulated by the prospect of profit, entrepreneurs will search different opportunities. And, the success or failure is decided by their search strategy.

On the set of projects, entrepreneurship is objective and exogenous whilst on the set of opportunities, it is often subjective and endogenous. Much of the confusion over opportunity has arisen because of the failure to distinguish properly between the project set and the opportunity set (p. 290). By subjective, it is because it reflects individual entrepreneurs' perceptions of prospective profits; by endogenous, it is because some of the unexplored projects which formed the basis for the opportunity set since entrepreneurs decided not to exploit them previously.

To make this transparent, the authors illustrated three stages involved in a project: discovery, investment, and operation.

At the first stage, Coordination in a project-based economy is necessary to understand entrepreneurial opportunity. In a volatile economy, the project portfolio needs to be continually updated; and there is always the competition with each project for scarce resources. Also, existing projects are competing with new projects to retain the resources already under their control (p. 290). Thus, there are always Complements and substitutes between projects. It is reasonable to allocate resources to the most promising projects. When there is conflicting projects, the provision that only one project could be undertaken is the most direct solution. Then, Infrastructure and knowledge is necessary to any type of project. The knowledge spill-overs could bring the opportunity in the future.

At the second stage, since Evaluating new projects is costly, it is important to find a strategy for economizing on the costs of entrepreneurial discovery. Here are two stages: one is to locate the fields where entrepreneurs intend to focus his search; and two is to examine a set of potential projects. The characteristics of each project would be the "symptoms of the projects' underlying profitability" (p. 293), since at this stage how profitable the project will be is unknown to anyone (p. 296). When evaluating, there are two approaches to do this. One is An inward-looking approach, where it focuses on the preferences and capabilities of the entrepreneur such as the lifestyle. Another is An outward-looking approach where the change in the trends in the long run were taken into entrepreneurs' consideration, such as technological change. Also in this approach, the performance of current projects will also be treated as the criteria for opportunity evaluation. Here, more projects of the best performing types will remained; or the projects whose significance was not appreciated by the previous investments will be emphasized.

At the third stage, different entrepreneurs might look different part of an opportunity and they tend to have different pools of information. This makes the Sequential screening different from each other. Essentially, the project which is felt uncertain would be put "on hold." Owing to their limited information and resources, entrepreneurs will carry one project at one time and terminate the project ASAP so that he can proceed to investigate others. Entrepreneurs are not working along, but they will have to take account of the choices of the field made by other entrepreneurs. Sophisticated entrepreneurs may be able to gain further advantage through the strategic exploitation of the social processes such as starting a rumor.