Compare methods

	Tobin's Q Firm Value Analysis	Diversification-Performance Analysis (Rumelt Categories)
Field	Strategic Management	Strategic Management
Family	Regression model	Process / pipeline
Year of origin	1981	1974
Originator	Eric B. Lindenberg & Stephen A. Ross; Kee H. Chung & Stephen W. Pruitt	Richard P. Rumelt; Krishna Palepu
Type	Market-valuation ratio used as a firm performance and rent measure	Classification-and-comparison pipeline relating diversification type to firm performance
Seminal source	Lindenberg, E. B., & Ross, S. A. (1981). Tobin's q Ratio and Industrial Organization. Journal of Business, 54(1), 1-32.	Rumelt, R. P. (1974). Strategy, Structure, and Economic Performance. Division of Research, Graduate School of Business Administration, Harvard University. ISBN: 9780875841090
Aliases	Tobin's Q Ratio Analysis, Market-to-Replacement-Cost Analysis, Q-Ratio Firm Performance Measure, Approximate Tobin's Q	Rumelt Diversification Category Analysis, Related vs Unrelated Diversification Analysis, Corporate Diversification Strategy Classification, Diversification Strategy-Performance Linkage
Related	3	3
Summary	Tobin's q is the ratio of a firm's market value to the replacement cost of its assets, and it serves in strategy and industrial organization as a forward-looking measure of value creation and economic rent. A q above one means the market values the firm at more than it would cost to rebuild its assets, signaling that the firm earns rents -- from market power, brands, technology, or hard-to-replicate capabilities -- beyond the competitive return on capital. Lindenberg and Ross's 1981 study brought q into empirical industrial organization, developing an algorithm to estimate the replacement cost of assets and showing how q relates to monopoly power and barriers to entry. Because exact replacement costs are laborious, Chung and Pruitt's 1994 paper introduced a simple approximation built entirely from standard accounting and market data that tracks the exact measure closely, making q practical for large-sample research on firm performance.	Diversification-performance analysis asks whether the kind of diversification a firm pursues — staying focused, expanding into related businesses, or building an unrelated conglomerate — is systematically associated with how well the firm performs. The categorical version originates with Rumelt's 1974 Strategy, Structure, and Economic Performance, which classified diversified firms by specialization and relatedness ratios into single-business, dominant-business, related, and unrelated types and found that related diversifiers tended to outperform unrelated ones. Palepu's 1985 study reframed diversification with the continuous Jacquemin-Berry entropy measure, again finding that related diversification was associated with superior profit growth, and showed how the index approach and Rumelt's categorical method can be combined to gain both objectivity and conceptual richness.