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Dynamic theories and models - Thomas Malthus and the dynamics of population growth

6 important questions on Dynamic theories and models - Thomas Malthus and the dynamics of population growth

What are variables in characteristic of time series?

Variables that have different numerical values for the same variable over time. e.g. The world population from 1800 to 2011 gives us 212 different annual numerical values for size of world population.

What is the difference between stock and flow variables?

Stock variable; A variable that leaves aside the practical difficulties. It can be measured at any particular moment in time. E.g. Population.

Flow variable; Birth and death cannot be measured at a particular moment in time, but over period of times, e.g. Year, month.

How can you represent the simple arithmetic of stock and flow variables?

Stock and flow diagram in which the stock is drained by the flow variables. The cloud gives the boundaries.

What is a causal loop diagram?

A vizualization of the causal relationship between de independent and dependent variable, and between the dependent and independent variable. Also called 'two way' causality.

e.g. Number of births, influences population, but higher population also leads to higher number of births. This is the so called feedback loop. The number of deaths are remained constant.

What is the ceteris paribus clause?

When there are two variables considered in the causal loop, and the other variables remain constant.

What is the difference between a reinforcing and balanced feedback loop?

A reinforcing feedback loop is a positive feedback loop.
A balanced feedback loop is a negative feedback loop.

The reingforcing loop tells us the other variable moves in the same direction as the influencing variable. E.g. When the number of births increase, the population size increases.

A balanced feedback loop tells us the other variable moves in the opposite direction as the influencing variable. E.g. When the number of deaths increase, the population size will decrease.

The question on the page originate from the summary of the following study material:

Research methodology an introduction to scientific thinking and practice | 9789043037884 | Jacobus Adrianus Maria Vennix

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