Arrange connected-scatterplot axes so time flows left to right

Arrange the two variables so the connected path progresses globally from left to right across the plot. For example, swap which series is on the x- or y-axis when the main sequence would otherwise run right to left in a static connected scatterplot.

Readers bring a strong left-to-right expectation for visual exploration and for imagined temporal sequences. When a connected scatterplot violates that expectation, they can reverse the story of the data even if they understand the axes and the points.

Mechanism: Left-to-right flow aligns the path with common reading and sequence habits, so readers are less likely to infer the wrong temporal order.

Evidence: In the translation study, temporal order was reversed in connected-scatterplot tasks, including simple copying and translation to and from dual-axis line charts; the paper recommends a left-to-right global flow of time to minimize this error in static graphics (Haroz et al., 2016).

• User Goal: Explain how two measures change over time.
• Task: Help readers follow the sequence of a paired time series correctly.
• Data: Two simultaneous time series sampled at the same times.
• Chart Setting: A static connected scatterplot in print or another non-animated setting.
• Audience: Readers who are unfamiliar with connected scatterplots.
• Success Criterion: Readers identify the start-to-end order without reversing time.

Break it when: The chart is interactive or animated and the motion itself guides viewers through a non-conventional reading direction. Why: The paper notes that interaction and animation on the web can help guide sequence reading when the path does not follow the usual left-to-right convention.

Sacrifice: You may need to place a variable on a less natural axis to preserve a left-to-right temporal path.
Risk: Left-to-right flow alone does not fully solve direction errors.
Mitigation: Pair the axis arrangement with explicit time-direction cues on the path.

Mistake: Keep a right-to-left main flow because the current variable assignment feels natural. Why it fails: Readers can reverse the temporal order even when they are only copying or translating the chart.

Failure Sign: A reader narrates the path backward or points to the wrong start and end.
Quick Check: Ask someone to point to the first and last point and describe the sequence without help from surrounding text.
Stronger Test: Compare the current axis assignment with a version that swaps the two variables and keep the version that produces fewer reversed readings.

• Swap the two variables across the x- and y-axes if that makes the path run more clearly from left to right.
• Recheck the path after the swap and confirm that the main temporal sweep no longer runs backward.
• If you must keep a non-left-to-right path, add explicit time-direction annotation to the line.