Estimation of interregional input–output table using hybrid algorithm of the RAS method and real-coded genetic algorithm

In this paper, we propose a method for improving the accuracy of the estimation of interregional input–output tables, by combining the RAS method and the real-coded Genetic Algorithm (GA); these are simple representative methods for the estimation of an interregional input–output table. By comparing the performance evaluation results obtained using the proposed method, the RAS method, and Simulated Annealing, we verified that the combination of the genetic algorithm and the RAS method can enhance the estimation accuracy of an interregional input–output table. In addition, performance is further enhanced by adjusting GA parameters.     

新疆旅游业投入产出分析

本文以新疆2002年和2007年投入产出表为依据,从直接消耗系数和完全消耗系数、感应度系数和影响力系数以及投入产出乘数效应这三方面对新疆旅游业进行投入产出分析后发现,新疆旅游业对新疆经济的推动作用有限,旅游业自身的发展依赖于交通运输业、批发零售业、住宿餐饮业及交通运输设备业的发展,且旅游业的发展并未带来交通运输业的显著发展。     

The RAS Approach in Updating Input–Output Matrices: An Instrumental Variable Interpretation and Analysis of Structural Change

The main purposes of the paper are to reconsider the rationale of the RAS method, and to attempt to improve on its interpretation and usefulness. The substitution and fabrication factors in the RAS method are interpreted as statistical estimates obtained by the method of instrumental variables. This enables the computation of asymptotic standard errors for the factors and the relative precision of the predicted technical coefficients. Furthermore, an adjustment cost minimization model to describe how a sector determines its substitution and fabrication factors is presented. The solutions of the model provide another rationale for the RAS method, and the associated Lagrangian multipliers can be useful for assessing structural constraints and structural change.     

市民双休日环城市带休闲旅游行为特征分析——以吉首市为例

环城市带是城镇居民休闲旅游的重要目的地。文章在阐述了环城市带休闲旅游研究意义和对休闲旅游“需要-动机-行为”模式进行分析的基础上，以实地调查为基础，对吉首市民双休日休闲旅游行为特征和旅游的RAS（休闲活动空间）进行了实证分析。     

Return of the inoperability

There has been unrest in the research community investigating the inoperability of an economic system under disaster situations. The inoperability input–output model (IIM), which is very popular in the risk management field, has become a center of argument, particularly from the input–output researchers, that IIM is a straightforward application of the standard Leontief input–output model. This paper revisits the concept of inoperability, rather than IIM, and proposes its new role in disaster impact analysis using a conventional tool, i.e. the RAS method, for illustrating how the inoperability of an economic system in the aftermath of disaster can be evaluated. The proposed framework is employed to examine the inoperability of industries resulting from the 1995 Kobe earthquake. The findings of the analysis reveal the usefulness of inoperability concept that can even incorporate resilience (gained operability) using the proposed framework of this paper.     

GRAS versus minimizing absolute and squared differences: a comment

Junius and Oosterhaven (2003) Junius, T. and Oosterhaven, J. 2003. The solution of updating or regionalizing a matrix with both positive and negative entries. Economic Systems Research, 15: 87–96. [Taylor & Francis Online] [Google Scholar] developed the GRAS algorithm that minimizes the information gain when updating input–output tables with both positive and negative signs. Jackson and Murray (2004) Jackson, R. W. and Murray, A. T. 2004. Alternative input–output matrix updating formulations. Economic Systems Research, 16: 135–148. [Taylor & Francis Online] [Google Scholar], however, claim that minimizing squared differences in coefficients produces a smaller information gain, which is theoretically impossible. In this comment, calculation errors are sorted out from differences in measures, and it is shown that the information gain needs to be taken in absolute terms when increasing and decreasing cell values occur together. The numerical results show that GRAS outperforms both sign-preserving alternatives in all but one comparison of lesser economic importance. Moreover, as opposed to the result of Jackson and Murray, they show that minimizing absolute differences consistently outperforms minimizing squared differences, which overweighs large errors in small coefficients.     

Cost-effectiveness analysis in the Spanish setting of the PEAK trial of panitumumab plus mFOLFOX6 compared with bevacizumab plus mFOLFOX6 for first-line treatment of patients with wild-type RAS metastatic colorectal cancer

Objective: To assess the cost-effectiveness of panitumumab in combination with mFOLFOX6 (oxaliplatin, 5-fluorouracil, and leucovorin) vs bevacizumab in combination with mFOLFOX6 as first-line treatment of patients with wild-type RAS metastatic colorectal cancer (mCRC) in Spain.

Methods: A semi-Markov model was developed including the following health states: Progression free; Progressive disease: Treat with best supportive care; Progressive disease: Treat with subsequent active therapy; Attempted resection of metastases; Disease free after metastases resection; Progressive disease: after resection and relapse; and Death. Parametric survival analyses of patient-level progression free survival and overall survival data from the PEAK Phase II clinical trial were used to estimate health state transitions. Additional data from the PEAK trial were considered for the dose and duration of therapy, the use of subsequent therapy, the occurrence of adverse events, and the incidence and probability of time to metastasis resection. Utility weightings were calculated from patient-level data from panitumumab trials evaluating first-, second-, and third-line treatments. The study was performed from the Spanish National Health System (NHS) perspective including only direct costs. A life-time horizon was applied. Probabilistic sensitivity analyses and scenario sensitivity analyses were performed to assess the robustness of the model.

Results: Based on the PEAK trial, which demonstrated greater efficacy of panitumumab vs bevacizumab, both in combination with mFOLFOX6 first-line in wild-type RAS mCRC patients, the estimated incremental cost per life-year gained was €16,567 and the estimated incremental cost per quality-adjusted life year gained was €22,794. The sensitivity analyses showed the model was robust to alternative parameters and assumptions.

Limitations: The analysis was based on a simulation model and, therefore, the results should be interpreted cautiously.

Conclusions: Based on the PEAK Phase II clinical trial and taking into account Spanish costs, the results of the analysis showed that first-line treatment of mCRC with panitumumab?+?mFOLFOX6 could be considered a cost-effective option compared with bevacizumab?+?mFOLFOX6 for the Spanish NHS.     

A within-trial cost-effectiveness analysis of panitumumab compared with bevacizumab in the first-line treatment of patients with wild-type RAS metastatic colorectal cancer in the US

Abstract

Aims: This analysis investigated the cost-effectiveness of panitumumab plus mFOLFOX6 (oxaliplatin, 5-fluorouracil, and leucovorin) compared with bevacizumab plus mFOLFOX6 in the first-line treatment of patients with wild-type RAS metastatic colorectal cancer (mCRC).

Materials and methods: The cost-effectiveness analysis was developed from a third-party payer perspective in the US and was implemented using a partitioned survival model with health states for first-line treatment (progression-free), disease progression with and without subsequent active treatment, and death. Survival analyses of patients with wild-type RAS mCRC from the PEAK head-to-head clinical trial of panitumumab vs bevacizumab were performed to estimate time in the model health states. Additional data from PEAK informed the amount of each drug consumed, duration of therapy, subsequent therapy use, and toxicities related to mCRC treatment. Literature and US public data sources were used to estimate unit costs associated with treatment and duration of subsequent active therapies. Utility weights were calculated from patient-level data from panitumumab trials in the first-, second-, and third-line settings. A life-time perspective was taken with future costs and outcomes discounted at 3% per annum. Scenario, one-way, and probabilistic sensitivity analyses were performed.

Results: Compared with bevacizumab, the use of panitumumab resulted in an incremental cost of US $60,286, and an incremental quality-adjusted life-year (QALY) of 0.445, translating into a cost per QALY gained of US $135,391 in favor of panitumumab. Results were sensitive to wastage and dose rounding assumptions modeled.

Limitations: Progression-free and overall survival were extrapolated beyond the follow-up of the primary analysis using fitted parametric curves. Costs and quality of life were estimated from multiple and different data sources.

Conclusions: The efficacy of panitumumab in extending progression-free and overall survival and improving quality of life makes it a cost-effective option for first-line treatment of patients with wild-type RAS mCRC compared with bevacizumab.     

中国贸易增长的能源环境代价

本文构建了1987～2006年的可比价格投入产出表,并以此为基础测算了贸易对中国能源消耗和S02排放的影响.结果表明,此期间出口含能量和出口含硫量增长迅速,且增速快于相应的进口含污量增速,同时能源和SO2的贸易条件也明显恶化.而出口含能量和出口含硫量之所以快速上升,这主要是出口规模迅速增长带来的规模效应.不过技术变动有效地抑制了上述规模效应.此外,结构效应很小,这意味着中国的出口结构变化对能耗和SO2排放的影响不大.     

A MULTI-OBJECTIVE ASSESSMENT OF INPUT–OUTPUT MATRIX UPDATING METHODS

This paper shows that important insights can be lost when assessing the relative performance of balancing methods solely based on individual optima. This is demonstrated through a multi-objective assessment. A trade-off curve between RAS and sign-preserving absolute differences (SPAD) is obtained based on the 60×60 Norwegian 2001 input–output table. The trade-off curve takes on a form that is close to a step function. This demonstrates that the solution surface around the RAS and SPAD optimums are very flat. Solutions can be identified that improve on the other objective or measure with little or marginal cost to the original objective function. Motivation for the assessment is provided, the technique applied is presented and the implications of the findings are discussed in an input–output and industrial ecology context.