@techreport{NBERw2205,
 title = "Firm Size and R&D Intensity:  A Re-Examination",
 author = "Wesley M. Cohen and Richard C. Levin and David C. Mowery",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Working Paper Series",
 number = "2205",
 year = "1987",
 month = "March",
 URL = "http://www.nber.org/papers/w2205",
 abstract = {Using data from the Federal Trade Commission's Line of Business Program and survey measures of technological opportunity and appropriability conditions, this paper finds that overall firm size has a very small, statistically in- significant effect on business unit R & D intensity when either fixed industry effects or measured industry characteristics are taken into account. Business unit size has no effect on the R & D intensity of business units that perform R & D, but it affects the probability of conducting R & D. Business unit and firm size jointly explain less than one per cent of the variance in R & D intensity; industry effects explain nearly half the variance.},
}