Reconciling Model and Information Uncertainty in Development Appraisal

This paper investigates the effect of choices of model structure and scale in development viability appraisal. The paper addresses two questions concerning the application of development appraisal techniques to viability modelling within the UK planning system. The first relates to the extent to which, given intrinsic input uncertainty, the choice of model structure significantly affects model outputs. The second concerns the extent to which, given intrinsic input uncertainty, the level of model complexity significantly affects model outputs. Monte Carlo simulation procedures are applied to a hypothetical development scheme in order to measure the effects of model aggregation and structure on model output variance. It is concluded that, given the particular scheme modelled and unavoidably subjective assumptions of input variance, simple and simplistic models may produce similar outputs to more robust and disaggregated models.

An empirical investigation of stalled residential sites in England

Drawing upon a national database of unimplemented planning permissions and 18 in-depth case studies, this paper provides both a quantitative and qualitative analysis of the phenomenon of stalled sites in England. The practical and conceptual difficulties of classifying sites as stalled are critically reviewed. From the literature, it is suggested that planning permission may not be implemented due to lack of financial viability, strategic behaviour by landowners and house-builders, and other problems associated with the development process. Consistent with poor viability, the analysis of a national database indicates that a substantial proportion of stalled sites are high density apartment developments usually is located in low house value areas. The case studies suggest that a combination of interlinked issues may need to be resolved before a planning permission can be implemented. These include; the sale of the land to house-builders, renegotiation of the planning permission and, most importantly, improvement in housing market conditions

The relationship between residential development land prices and house prices

There exists apparent disagreement between two areas of literature regarding the relationship between house prices and land prices. In the professional literature it is argued that high house prices cause high residential development land prices. In some of the policy literature it is argued that it is land price increases that are behind increasing house prices. We argue that this is a rather artificial dichotomy and arises from two different ways of thinking about the relationship between land and house prices. To demonstrate this we explore how housing and residential land markets work and how their price responses are interrelated

Performance metrics and required returns for UK real estate development schemes

Real estate development has received less scrutiny than real estate investment in terms of appraisal practices and performance measurement. This is despite the inherent uncertainty and financial risks associated with development as an activity. We investigate market practices regarding performance metrics and return expectations both for residential and commercial real estate development in the UK, exploring what is considered as an appropriate return and how this varies according to type and duration of scheme, and method of appraisal used. After examining the literature and the information available on ex-post returns from development activity, results from a survey of real estate developers are reported, supplemented by findings from interviews. The results suggest that the use of traditional residual valuation techniques dominates discounted cash flow models when appraising development projects, particularly among residential developers, while profit-on-cost and profit-on-value are the most popular metrics for quantifying required returns. Unlike NPV or IRR, these metrics do not account for the timing of cash flows, raising questions about the robustness of appraisals in this sector. Such metrics might suffice if required profits are adjusted in ways that are consistent with scheme duration and risks, but it is unclear that this is currently the case. Keywords Development; Housebuilding; Profit Measures; Real Estate Appraisal; Required Return

Evidence for alterations in fixational eye movements in glaucoma

BACKGROUND: Fixation changes in glaucoma are generally overlooked, as they are not strikingly evident as in macular diseases. Fundus perimetry might give additional insights into this aspect, along with traditional perimetric measures. In this work we propose a novel method to quantify glaucomatous changes in fixation features as detected by fundus perimetry and relate them to the extent of glaucomatous damage. METHODS: We retrospectively analysed fixation data from 320 people (200 normal subjects and 120 with glaucoma) from the Preferred Retinal Locus (PRL) detection of a Compass perimeter. Fixation stability was measured as Bivariate Contour Ellipse Area (BCEA), and using two novel metrics: (1) Mean Euclidean Distance (MED) from the Preferred Retinal Locus, and (2) Sequential Euclidean Distance (SED) of sequential fixation locations. These measures were designed to capture the spread of fixation points, and the frequency of position changes during fixation, respectively. RESULTS: In the age corrected analysis, SED was significantly greater in glaucomatous subjects than controls (P = 0.002), but there was no difference in BCEA (P = 0.15) or MED (P = 0.054). Similarly, SED showed a significant association with Mean Deviation (P  0.14 for both). CONCLUSION: Changes in the scanning pattern detected by SED are better than traditional measures of fixation spread (BCEA) for describing the changes in fixation stability observed in glaucoma

State regulation of land financialisation: Land promoters, planning risk and the land market in England

The paper contributes to existing research that examines how government policy and state actors support the financialisation of land via the development process and, as such, how planning systems have facilitated the accumulation of privately-owned land-based wealth. The empirical focus of the research is the specialist residential land promoter sector in England. This is a particularly appropriate case study because of the way in which this sector of the land market has become integrated with the planning system via crisis-driven planning reform that has facilitated the commodification of planning risk and, thus, the financialisation of land. The paper examines the diversity of business models, practices and strategies of land promoters to show how they have been shaped both by the politics of planning reform as well as the financial objectives of their funders. The research is therefore in dialogue with wider international literature on the relationship between planning and the land market, how this relationship may be conceptualised via risk and uncertainty, and the role of state regulation in reshaping the physical environment in accordance with financial logics

Development appraisal in practice: some evidence from the planning system

Due to the requirement to demonstrate financial feasibility of policy proposals and scheme-specific planning obligations, development viability and development appraisal have become core themes in the English planning system. The objective of this paper is to evaluate the application of development appraisal in practice. The paper reviews the literature and the models available to assess the viability of development and analyses a sample 19 development viability appraisals to identify practice. The paper concludes that the practice of development appraisal deviates significantly from the tenets of capital budgeting theory. In particular, in addition to a propensity to oversimplify the timing of income and expenditure, the way in which debt, developer’s return and value and cost change are handled in practice illustrates a major gap between mainstream capital budgeting theory and development appraisal in practice

A novel binary pesticidal protein from Chryseobacterium arthrosphaerae controls western corn rootworm by a different mode of action to existing commercial pesticidal proteins.

The western corn rootworm (WCR) Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae) remains one of the economically most important pests of maize (Zea mays) due to its adaptive capabilities to pest management options. This includes the ability to develop resistance to some of the commercial pesticidal proteins originating from different strains of Bacillus thuringiensis. Although urgently needed, the discovery of new, environmentally safe agents with new modes of action is a challenge. In this study we report the discovery of a new family of binary pesticidal proteins isolated from several Chryseobacterium species. These novel binary proteins, referred to as GDI0005A and GDI0006A, produced as recombinant proteins, prevent growth and increase mortality of WCR larvae, as does the bacteria. These effects were found both in susceptible and resistant WCR colonies to Cry3Bb1 and Cry34Ab1/Cry35Ab1 (reassigned Gpp34Ab1/Tpp35Ab1). This suggests GDI0005A and GDI0006A may not share the same binding sites as those commercially deployed proteins and thereby possess a new mode of action. This paves the way towards the development of novel biological or biotechnological management solutions urgently needed against rootworms