5.3.7. Ladder Plot

The ladder plot shows the relationship between the ranks of data in two columns. This plot is used (usually) to visualise the effects of a treatment on the same set of subjects before and after a treatment. Select the two columns using [Column 1] and [Column 2] from the Variable Selection Dialogue.

Each bar on the ladder represents a row of data. The ranks of data in each row are plotted on the left and on the right of the ladder for columns 1 and 2 respectively. The same numbers on either side are then connected by a line. Therefore, if a row has the same rank in both columns, its bar will be horizontal.

The plot can be split into a number of ladders laid out side by side instead of one single ladder. This is useful for plotting columns with a large number of rows. The ranking can be in Ascending or Descending order. All these options can be controlled from Edit → Ladders dialogue.