Combining agile methods with stage-gate project management

We encountered cultural changes and different management and engineering viewpoints in a study of three large software development organizations that started using agile methods. Case studies at three large software product companies show the benefits and pitfalls of integrating agile methods with stage-gate management models.     

The role of emigration and migration in Swedish industrialization

It is possible, within a general equilibrium framework, to reveal some of the important mechansims in the rather complicated interplay among the variables causing demoeconomic development. The model for this study is a computable general equilibrium model within the tradition of multisectoral growth models and is designed to fit Swedish prewar development and to enable counterfactual analysis. The model is reviewed briefly followed by comments on the database, estimation procedure and validation; displays of some comparative static experiments; and an evaluation of the capability of the model in replicating Swedish demoeconomic development between 1871-90 before examining the counterfactual simulations which address the role of external and internal migration in Swedish industrialization. There are at least 2 reasons for carrying out comparative static experiments: by undertaking parameter changes and exploring the equilibrium effect on the model, further insights will be realized concerning the behavior of the model and its validity; and some of the comparative static experiments are interesting from the point of view of policy analysis because they reveal the static, total effect on the economy of changes in some variables discussed by 19th century Swedish politicians. The experiments are organized into 2 groups: rural and population experiments. The base run simulation from 1871-90 indicates that the model captures the essential factors of the demoeconomic development of Sweden. The model's ability to replicate historical trends in some of the crucial variables permits use of the base simulation as a reference point when undertaking counterfactual simulations. The 1st simulation evaluates the effects of emigration on the Swedish economy; the remaining 2 simulations assess the importance of rural to urban migration. The model indicates that without emigration real rural wages would have been 1.8% lower in 1880 and 10.0% lower in 1890. Urban wages would have been unaffected in 1880 but 1.5% higher in 1890. Emigration apparently had a positive effect on the standard of living in the rural areas, but possibly even larger rural to urban migration than occurred in the simulation would have happened in the absence of emigration. Rural to urban migration apparently had a significant growth creating effect. The reallocation of labor force to the more dynamic and high wage urban sector with its modern technology and higher rate of productivity change was of great importance to the economic performance of the national economy. More rural to urban migration has a temporary growth creating effect, but in the long run this effect disappears, because it also decreases the wage gap between rural and urban areas and consequently has a boomerang effect on itself.     

Indirect spinal canal decompression in burst fractures treated with pedicle screw instrumentation

STUDY DESIGN: Prospective evaluation of spinal canal areas in 67 consecutive burst fractures between T12 and L2 treated by reduction and stabilization with a pedicle fixator. OBJECTIVES: Assessment of the efficacy of "indirect" spinal canal decompression in a large series of burst fractures. SUMMARY OF BACKGROUND DATA: Up to 50% of burst fractures cause neurologic impairment. Reduction and posterior instrumentation is the most common surgical treatment. This also reduces spinal canal encroachment by indirect decompression. No consensus exists as to the consistency and adequacy of such indirect decompression. METHODS: Spinal canal areas were measured on preoperative and postoperative computed tomography scans. The degree of encroachment was compared with clinical and radiographic variables for possible correlation. RESULTS: Spinal canal encroachment was more severe among patients with neurologic deficits than among the neurologically intact. Postoperatively, mean encroachment was reduced from 35% to 12% at T12, from 37% to 17% at L1, and from 52% to 35% at L2. Loss (and postoperative restoration) of anterior vertebral height correlated best with the degree of canal encroachment (and its reduction), especially in Denis Type A burst fractures. In Denis Type B fractures, canal compromise usually was less severe and fragment reduction better in patients older than 40 years of age than in younger patients. CONCLUSIONS: Indirect decompression in burst fractures averages about half of the preexisting encroachment. Results are usually better at T12 and L1 than at L2. Additional or secondary decompression is rarely indicated if these fractures are treated early and by experienced surgeons. Burst Type B fractures in patients older versus younger than 40 years of age differ in many respects.