8.1 Investigating Human Population Dynamics

Investigating Human Population Dynamics

This is one of my favourite investigations and ESS students generally love this topic. It can involve handling a lot of data and so is good practice for using Excel and learning how to process data. It never worked very well for the old version of the lab assessment criteria but with the new Independent Investigation criteria it offers the basis for some interesting research. When my students trialed the new Investigation several of them chose to research something along the lines of this practice lab. These are the instructions I give to my students but I walk them through each step, helping them develop research questions, use Excel, processing the data, and choosing suitable countries to extend their discussions. Gapminder compiles statistical information about demographics and socio-economic data. We will use this site to generate data for a range of countries and then map demographic statistics and population growth rates.

A good introductory video from Hans Rosling although there are many other excellent talks from Hans:

Here's a compilation of Hans Rosling Videos

Investigating the relationship between a socio-economic factor and a demographic factor

The idea behind this investigation, is to help students understand some simple relationships between socio-economic factors and demographic factors. It also helps them develop their use of Excel to produce tables, plot scatter graphs and find the R2 value to check for a correlation. The data available in Gapminder and other sites can be used to investigate other relationships for the Independent Investigation, using the same strategies in this investigation.

Students will produce a mini-report on their investigation using a mini-version of the IA template, training them to move away from a standard science lab report.

What is a socio-economic factor in this investigation?

We are looking for factors that you would hypothesise have had an impact on slowing population growth. In this investigation, we are looking for data to confirm what we would expect based on the demographic transition model and your understanding of population dynamics. These examples cover many different data types in Gapminder.

Examples include:

  • Literacy
  • Years in school
  • Use of contraception
  • Health care availability
  • Disease
  • Income
  • Female employment
  • Human Development Index

What is a demographic factor in this investigation?

We are looking for factors that you would hypothesise would indicate slowing population growth and socio-economic status. These examples cover several data types in Gapminder.

Examples include:

  • Crude birth rate
  • Crude death rate
  • total fertility rate
  • infant mortality
  • life expectancy

Step 1

PRELIMINARY RESEARCH - Use Gapminder Tools to check if two factors have a relationship - test your hypothesis. The socio-economic factor should be on the x axis (independent variable) and the demographic factor on the y axis (dependent variable) as you are hypothesising that the socio-economic factor changes are having an impact on the demographic factor.

Step 2

Finalise your RESEARCH QUESTION. It should look something like this:

"To what extent is the crude birth rate of a country impacted by the level of literacy in females?"

Step 3

Research and write about 100 - 200 words explaining the CONTEXT of your research. Explain why you are looking at the relationship between these two factors.

Step 4

Decide upon your SAMPLING STRATEGY. You need to collect sufficient data to answer your question. The minimum number of countries to include in your analysis is 30 countries to provide enough data to have more validity in your conclusions. You need to decide how to sample the available data. One method is to include all countries which are common in both data sets (maximum available sample size). Another method is to randomly sample the countries based on a random number selection or a method based on the alphabet. Finally, you may want to choose countries based on some other data, such as the income bracket of a country. You could use the World Bank Open Data for this. You should be aware that this may bias your data but it is a valid sampling strategy.

Step 5

Go to Gapminder Data and download your data. For an Independent Investigation you should consider that there are other sources for such data and that it might be worth finding multiple sources of data for your investigation then calculating means of the data. The data comes as an Excel or csv file and you should check that you can access the data.

Choose data from one common year in both sets of data. Try to find the most recent common year with lots of data. If you need to use two different years, then you will need to comment on this in your evaluation of the data.

Copy the data into one file with three columns. 

CountrySocio-Economic Data (Year and Units)Demographic Data (Year and Units)

Edit the data so that you have the data aligned correctly for each country (this is trickier than you might think). Allow about 30 minutes.

Step 6

Plot a scatter graph of your data. Add a trendline and the R2 value. Improve the presentation of your graph with an informative title, labels on the axis and gridlines that aid interpretation. Excel does not name the countries on the scatter plot and so you need to use your data table to identify any particular points on your graph. In order to have your socio-economics factor on the axis axis, it should be in your first column of data.

Here is an example

Here's a video to help. Please note that the gridlines should be retained and the series label removed.

Here's a video to add the trendline and R2 value with a nice explanation of what the R2 value means.

Step 7

Identify 3 countries which you will use to discuss your data and the pattern that it demonstrates.  Research some background information about these countries, such as their position in the demographic transition model and the population policies in place in these countries. You could also check their Sustainable Development Goal setting (SDGs). You may want to include a Gapminder bubble graph to enhance your discussion of the data as this gives you additional information such as population size and geographical region. You could also find a population pyramid and a predicted population pyramid for the three countries you elaborate upon.

Step 8 

Complete your report. It should include:

  • Context - What are you investigating and why?
  • Research Question
  • Sampling Strategy - how are you investigating your RQ
  • Data - Graph of data with trendline and R2 value
  • Data Analysis - Description of the trend and statistical support for the correlation.
  • Discussion - Put the trend into context with the use of 3 countries and how they fit or do not fit the pattern seen.
  • Future Research - how could you take this further and what would you improve?
  • References / Bibliography (have you in-text cited?_
  • Appendix - include a data table of your data

Useful Reference Sources:

Gapminder - The Rosling family's non-profit organisation furthering the UN's sustainable development goals.

Population Reference Bureau. Population Data Sheet and fact sheets

US Census Bureau International Database Search Facility

CIA The World Factbook

United Nations Statistics Division

World Bank Data - this is useful for categorising countries according to their income.

Here's Hans Rosling showing you how to use Gapminder:

Tip: This is a good opportunity to talk about correlation and causation. Here's some funny graphs to get the point across.

Here's an interesting TEDx talk on the topic.

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