The waterfall model is a traditional engineering approach applied to software engineering. A strict waterfall approach discourages revisiting and revising any prior phase once it is complete. This "inflexibility" in a pure waterfall model has been a source of criticism by supporters of other more "flexible" models. It has been widely blamed for several large-scale government projects running over budget, over time and sometimes failing to deliver on requirements due to the Big Design Up Front approach. Except when contractually required, the waterfall model has been largely superseded by more flexible and versatile methodologies developed specifically for software development. See Criticism of Waterfall model .
This quality review (December 2012) is in three main parts:
-Part I reports the results of a first self-assessment of different quality dimensions of the OECD Database on Household Income Distribution and Poverty ( .pdf )
-Part II assesses the cross-country comparability of the OECD Earnings Distribution Database ( .pdf )
-Part III provides detailed country data reviews on income distribution data, for the 34 OECD member countries. These country reviews compare the OECD benchmark series for income distribution and poverty reporting with alternative estimates which are available on a national or international basis - each country separately (.pdf) including revised versions:
This training method is chosen while preparing a second-line leader to take up the role of the headship, in which case, the candidate could not benefit by sending them to any other formal training program. The best way to be trained for a future executive position would be through direct participant observation of the crucial events that take place in the present incumbent’s work life. The trainees are made to remain in the company of the role model whose work is to be learnt by the trainees. Trainees learn the intricacies of a job of high level, by physically being in the presence of the job-holder. Closely following the styles of working permits greater degree of learning besides helping the trainee to imbibe the values and principles adhered to by the model. Yet, care needs to be taken to avoid situations wherein trainees are not warmly welcomed and are seen by supervisors in the department as obstacles to their routines.