System dynamics on time wastage or management | Coursera Community
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System dynamics on time wastage or management

  • 24 July 2020
  • 4 replies

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Hello colleagues, hope y'all are fine? I am trying to come with a system dynamics model for time management/wastage. I want to look at it in terms of cost, production and percentages. That is, how mush does it cost us when we waste time that would have been used for productive activities? I mean, can time be a stock and use a time use as the rate?

Any advise will be appreciated

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@EstherMews   Welcome to the forum!

Thanks for posting two questions for discussion.  I’ll share what little I know about the first question, and ask you to clarify the second one that I have difficulty understanding.

To your first question, that is what economists would tag it as opportunity cost.  The cost of time wasted can be equate to the value that the productive activities would bring.  In a simplified case that a person is paid by the hour worked, when a person starts work an hour late or leaves work an hour early doing whatever is considered time wasted, the opportunity cost is an hour of pay.

As for the second question “can time be a stock and use a time use as the rate?”, I have difficulty deciphering.  For example, “can time be a stock?”  can be answered depending on the context.  I can think of at least one example, say accrued vacation and/or sick time.  As for the rest of the question “and use a time use as the rate?”, I can hazard a couple of guess, but why waste time, right? 


Recall that stocks contain something that is measurable when ‘time’ is stopped. Time Available would be a stock. You now have multiple flows out of that stock. One may be useful time spent, another may be wasting time. It would be best to make both of these flow a percentage of the stock so that the Time Available stock does not go below zero.

Now, how do you allocate those two (if not more) flows the correct percentages? We know that in a specified duration, e.g. a week, Time Available cannot be more than 24  hours/day * number of days. What are the dynamics that cause you to increase/decrease/maintain constant the flow? That is where opportunity cost and marginal utility come to play. As the value of the flow (actually time/time, e.g. Time Available * 30%/day for sleep) changes it is based on the utility to you of spending one more unit of your Time Available stock on each activity.


That’s the difficult part, what are the behavioral dynamics of that allocation? Economic theory says that when spending time on multiple activities it is hypothesized that we make the ration of marginal utility to cost equal for all activities. More simply, depending on how much time we spend on all the different things we do, spending one more minute on anything, will give equal utility. Ceteris paribus, we assumed rationality and perfect information.

This is an interesting problem that intersects system dynamics and economics.

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@ele81946. Thanks for the reply. It has cleared a few things for me. What i meant was that if i were to formulate a system dynamics model with stocks and flows, Can TIME be a stock and any time used- TIME USE, be the rate at which time flows out? I am looking at all the different things that take up our time  some of them may be mindless. The question is how much time do we loose?


Yes, the stock should be Time Available. Since SD models run over time Time itself cannot be a stock. As you drain the Time Available stock the rates will be something like %/hour allocated to each of the flows out of Time Available. The tricky part is that the software uses the word Time to manage the math. You will have to create a special unit for Time available.