This model describes phosphorus cycling in a dune-lake system in the Northland region of New Zealand. It is based on stock and flow diagrams where each orange oval represents an input, while each blue box represents a stock. Each arrow represents a flow. Flows involve a loss from the stock at which they start and add to the stock at which they end.

From Walrave ISDC2014 paper Counteracting the success trap in publically owned corporations

WIP based on Emery Roe's 2013 book. See also Dynamics in Action IM-3239 for more on behavior and The Art of the State IM-11962 for more on Grid-Group Cultural Theory

This diagram provides an accessible description of the key processes that guide the water quality within a lake.

Addition of an acceptance test which discovers rework (Cooper et al.) plus introduction of new tasks and tipping point (Taylor and Ford). Here schedule pressure producing overtime is also added

This model incorporates several options in examining fisheries dynamics and fisheries employment. The two most important aspects are the choice between I)managing based on setting fixed quota versus setting fixed effort , and ii) using the 'scientific advice' for quota setting  versus allowing 'political influence' on quota setting (the assumption here is that you have good estimates of recruitment and stock assessments that form the basis of 'scientific advice' and then 'political influnce' that desires increased quota beyond the scientific advice).

This model incorporates several options in examining fisheries dynamics and fisheries employment. The two most important aspects are the choice between I)managing based on setting fixed quota versus setting fixed effort , and ii) using the 'scientific advice' for quota setting  versus allowing 'political influence' on quota setting (the assumption here is that you have good estimates of recruitment and stock assessments that form the basis of 'scientific advice' and then 'political influnce' that desires increased quota beyond the scientific advice).

Addition of an acceptance test which discovers rework (Cooper et al.) plus introduction of new tasks and tipping point (Taylor and Ford)

This model incorporates several options in examining fisheries dynamics and fisheries employment. The two most important aspects are the choice between I)managing based on setting fixed quota versus setting fixed effort , and ii) using the 'scientific advice' for quota setting  versus allowing 'political influence' on quota setting (the assumption here is that you have good estimates of recruitment and stock assessments that form the basis of 'scientific advice' and then 'political influnce' that desires increased quota beyond the scientific advice).

Addition of an acceptance test which discovers rework (Cooper et al.) plus introduction of new tasks and tipping point (Taylor and Ford). Here schedule pressure producing overtime is also added

Control de Stocks

This stock and flow diagram is a working draft of a conceptual model of a dune-lake system in the Northland region of New Zealand.

This model incorporates several options in examining fisheries dynamics and fisheries employment. The two most important aspects are the choice between I)managing based on setting fixed quota versus setting fixed effort , and ii) using the 'scientific advice' for quota setting  versus allowing 'political influence' on quota setting (the assumption here is that you have good estimates of recruitment and stock assessments that form the basis of 'scientific advice' and then 'political influnce' that desires increased quota beyond the scientific advice).

Public utilities do not need to make a profit. They can concentrate on providing a quality service, a public good. By contrast, the primary objective of private utilities is not to provide a public good, but profit and profitability. This simple CLD tries to show the conflict that can arise from this and a hidden dynamic, a reinforcing feedback loop, that can lead to disaster. Unfortunately, there are examples where failure in infrastructure maintenance has led to disaster. On the 9th of July 2009, the German newspaper 'Welt Online' reported that the authorities in Berlin had to intervene and force the company that was running Berlin's S-Bahn (suburban rail service) to withdraw half of all the city's trains from service because they were considered unsafe! Something similar happened in the UK where failure to maintain rail tracks led to serious accidents. 

Rich picture causal loops unfolding version of Insight 714, Based on Lyneis JM and Ford DN System Dynamics Applied to Project Management Syst. Dyn. Rev. 23, 157-189 (2007)

Project management in an ideal world. The project has a defined scope, work rate and runs according to the initial schedule.

Schedule pressure is constant until the project is completed.

From Walrave ISDC2014 paper Counteracting the success trap in publically owned corporations

This stock and flow diagram is a working draft of a conceptual model of a dune-lake system in the Northland region of New Zealand.

Addition of an acceptance test which discovers rework (Cooper et al.) plus introduction of new tasks and tipping point (Taylor and Ford)

Addition of an acceptance test which discovers rework (Cooper et al.) plus introduction of new tasks and tipping point (Taylor and Ford). Here schedule pressure producing overtime is also added