---

The importance of productivity has made it to be one of the most serious discussions in industrial organizing. In economic literature, however, there are some arguments on the role of market structure in productivity changes. While some theorists point out that more competition leads to higher productivity, others believe that monopoly environment would be more efficient. This study examines the effect of competition- that is measured by the number of firms- on labor productivity in the Iranian industries. Using the panel data from the firms hiring 10 employees or more, the results suggest that monopoly and private ownership provide a more suitable environment for reaching higher productivity.

---

The main objective of this paper is to evaluate the effect of R&D on profitability of high -tech industries with new evidence from the Iranian industries carrying four- digit codes. The Structure- Conduct- Performance (SCP) paradigm, which is relatively well known in industrial economics and in organization management, provides the theoretical construct that guides our empirical model formulation and execution.  The data is compiled from observations made at the plant level covering all industrial plants employing ten or more persons and carrying four- digit codes within the time span of 1994-2007. The model used essentially consists of a simultaneous equation system framework grounded into a panel data approach and estimated by Two-Stage Least Squares (2SLS). Our findings indicate a positive and significant effect of R&D expenditures, measured in intensive form, on profitability of high-tech industries as evidenced by the Iranian case. Our more notable finding is the positive effect of lagged profits on R&D expenditure intensity, revealing a likely mutually enforcing relationship between profitability and R&D intensity in high tech industries