Authoring a PhD Thesis How to Plan, Draft, Write and Finish a Doctoral Dissertation by Patrick Dunleavy

HANDLING ATTENTION POINTS◆ 179

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JFMAMJ

Month

Percentage

% ‘Very good’ % ‘Fairly good’

JASOND

0

(g) Layer chart

Proportion of UK survey respondents rating the
performance of the railways as ‘very good’ or
‘fairly good’, 2001 (hypothetical)

Use a layer chart whenever:

• you want to show how the relative size of two
  positively associated variables varies across time.

Don’t use a layer chart if:

• your two variables are not really linked.

Points to watch:

• put the layers in an order that gives the clearest visible
  pattern, e.g. a numerical progression with the largest
  layer at the bottom and smaller layers towards the top;


• if the variables have to be kept in a fixed sequence but
  this gives a jumbled appearance to the layers, then use
  another type of chart.