Data Journalism

Chris Knox

Data Editor at the New Zealand Herald (in August 2020)

30 July, 2020



  • Styling
  • Chart choice
  • Transpose
  • Maps

What is a visualisation?

Using the visual modes available; size, colour, shape, and position to represent (encode) the values in the data.

It it usual for quantities to be proportional to the area of the visual encoding - this makes circles very poor for accurate comparisons of values.

It’s actually quite old

Drawing time

2017 Election Party Vote

Party Votes Percent
National Party 1,152,075 44.4
Labour Party 956,184 36.9
New Zealand First Party 186,706 7.2
Green Party 162,443 6.3
The Opportunities Party (TOP) 63,261 2.4
Māori Party 30,580 1.2
ACT New Zealand 13,075 0.5
Aotearoa Legalise Cannabis Party 8,075 0.3
Conservative 6,253 0.2
MANA 3,642 0.1
Ban1080 3,005 0.1
New Zealand People’s Party 1,890 0.1
United Future 1,782 0.1
NZ Outdoors Party 1,620 0.1
Democrats for Social Credit 806 0.0
Internet Party 499 0.0

2017 Election Party Vote by Voting Type

Type Votes Percent
Election Day 1,151,123 44.4
Advance 1,022,793 39.5
Special 375,726 14.5
Party Only 42,254 1.6

2017 Election Party Vote by Voting Type and Party

Advance Voting

Party Type Votes Percent of type Percent of party
ACT New Zealand Advance 4,690 0.5 35.9
Green Party Advance 64,172 6.5 39.5
Labour Party Advance 375,298 38.2 39.2
National Party Advance 464,939 47.3 40.4
New Zealand First Party Advance 72,979 7.4 39.1

Election Day Voting

Party Type Votes Percent of type Percent of party
ACT New Zealand Election Day 6,283 0.6 48.1
Green Party Election Day 63,609 5.8 39.2
Labour Party Election Day 402,962 36.7 42.1
National Party Election Day 534,259 48.6 46.4
New Zealand First Party Election Day 91,149 8.3 48.8

Party only votes

Party Type Votes Percent of type Percent of party
ACT New Zealand Party Only 153 0.4 1.2
Green Party Party Only 2,633 6.8 1.6
Labour Party Party Only 22,144 57.0 2.3
National Party Party Only 11,149 28.7 1.0
New Zealand First Party Party Only 2,789 7.2 1.5

Special votes

Party Type Votes Percent of type Percent of party
ACT New Zealand Special 1,949 0.6 14.9
Green Party Special 32,029 9.1 19.7
Labour Party Special 155,780 44.3 16.3
National Party Special 141,728 40.3 12.3
New Zealand First Party Special 19,789 5.6 10.6

Bad or deceiving charts

  • Charts and graphs can be used to deceive
    • Don’t do this.

The best way to get a sense for bad charts is to peruse or /r/dataisugly. There is also a good writeup here

In the New Zealand context Stats Chat is great.

The most common bad things are:

  • Incorrect, missing, or misleading labels
  • Inconsistenct scales
  • Truncating scales
  • Comparing things that shouldn’t be
  • Too many things

A few rules

  • Barcharts always start at 0
  • Line charts don’t need to start at 0, but always ask yourself if the range you select is going to make an insignificant change look important
  • Only use pie charts for
    parts of a whole
    and only when there are less than 5 categories
  • Avoid maps for showing quantities


Pick a couple of charts from Figure.NZ and remake it.

  • Have you made them better or worse?
  • If you have improved them is the data being shown in a different way?


In pairs discuss these:

  • What do you think of these approaches?
    • Do you like them?
    • Are there other ways you would prefer to learn about this data?
  • Are they journalism?
  • Are they news?

NZH Improvements

I probably should have included a median income version as well as an average income version.

Digressions — Why?

All summary statistics hide things

The mean and standard deviation are the same for each of these graphs


  • Select some data with two variables from Figure.NZ
  • Clean and reshape the data in Workbench
  • Export the data to Datawrapper and create a chart
  • Email the chart link to and share the Workbench workflow with me
  • Include a sentence about why you choose this data - why would it be newsworthy
  • If you changed to chart type from the Figure.NZ default include a sentence about why you choose that chart type.