Two goal seeking structures attempting to resolve and based on the delay one may tend to settle for less. There is also a video for this model which is a component of the Systems Archetypes Course.
This structure begins with a standard Goal Seeking structure which attempt to move [what i have] to the desired state [what i want] via the [action to get what i want].
Though there's a difficulty that often arises because of the delay associated with getting from [action to get what i want] moving [what i have] to [what i want]. The Goal Seeking loop B2 is also capable of relieving the tension which is the [gap].
If the [pressure to settle for less] is great enough so it reduces [what i want] then the [gap] is reduced. Which is why this is called a Drifting Goals structure. There are two ways to relieve the tension and one is generally easier and takes less time than the other.
The equivalent Stock & Flow structure adds [pct chg fact] to govern the extent to which [tension] affects [action] and [goal chg fact] to govern the extent to which [tension] affects [goal reduction].
Running the simulation with [desired state] = 1, [current state] = 0, [pct chg fact] = 0.2 and [goal chg fact] = 0 we get the typical goal seeking structure behavior though it takes almost 20 weeks to reach the goal. This may be perceived as taking way too long and cause frustration.
If we change the value of [goal chg fact] = 0.05 we notice a marked reduction in the [desired state] and hence it doesn't take nearly as long to reach the goal.
If we set [pct chg fact] = 0.5 and run the simulation we note that it takes much less time to reach the [desired state] and it declines far less.
It should be apparent that the the extent the goal drifts is dependent both the time it takes to move in the desired direction and the willingness to deal with the tension created by not yet being there.
Strategy: The two effective strategies for dealing with this structure are: 1) disconnect the [pressure to settle for less] from [what i want] so it can't cause the goal to drift; 2) Increase the rate at which there is progress toward [what i have] so there's less time for the goal to drift. The viability of either of these will depend on the actual elements in the structure.
Change the sliders to run the model with various parameters to see how they impact the behavior of the model. Also change the Simulation Time Step in Settings to 1, .5, .25, and .125 to see how this affects the nature of the graphs.