Most work on valuing the recreational benefits of public forests has concentrated on estimating consumers' surplus per visit. W e use two contingent valuation approaches to try to place a value on the physical characteristics of British forests, and hence to explain the variation in consumers' surplus across different forest types. Our two approaches are, first, to obtain incremental willingness-to-pay to access forests with different levels of a number of characteristics by showing visitors pairs of photographs; and second, to use characteristic levels as explanatory variables in a bid curve. W e find that forest characteristics are in generalpoor predictors of willingness topay.

Both theoretical and empirical labour market papers that incorporate the workers-hours dichotomy often contain assumptions about shapes of the overtime premium schedules faced by industry. Using cross-section data for British production industries in three years of sharply contrasting economic climates (1981, 1984 and 1988), this paper investigates empirically the appropriate choice of schedule and, therefore, the industrial cost consequences of changing the average number of overtime hours per period. The analysis tackles problems associated with data disaggregation, the proportion of workers working overtime, omitted variables, heteroscedasticity and intertemporal variation

Summary1. Conservation and natural resource management challenges are as much social problems as biological ones. In recognition of this fact, ecologists and economists work increasingly closely together. We discuss one barrier to effective integration of the two disciplines: put simply, many ecologists and economists approach statistical regression differently. 2. Regression techniques provide the most commonly used approach for empirical analyses of land management decisions. Researchers from each discipline attribute differing importance to a range of possibly conflicting design criteria when formulating regression analyses. 3. Ecologists commonly attribute greater importance to spatial autocorrelation and parsimony than do economists when designing regressions. Economists often attribute greater importance than ecologists to concerns about endogeneity and conformance with a priori theoretical expectations. 4. Synthesis and applications . The differing importance attributed to different design characteristics may reflect a process of cultural drift within each discipline. Greater interdisciplinary collaboration can counteract this process by stimulating the flow of ideas and techniques across disciplinary boundaries.

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