plot_mean_time()

plot_mean_time() draws a horizontal bar chart showing, for each state, the average amount of time spent in that state across all sequences. Optionally, it adds standard error bars so you can judge uncertainty.

Example: if your sequences cover 10 years and the average person spends 2.8 years in “Education”, the bar for “Education” is 2.8 (on the x-axis). Units follow your data (years, months, waves, etc.).

Function Usage

plot_mean_time(
    seqdata,
    show_error_bar=True,                 # add SE whiskers
    title=None,                          # optional figure title
    x_label="Mean Time (Years)",         # change to "Months" / "Waves" as needed
    y_label="State",
    save_as=None,                        # e.g., "mean_time.png"
    dpi=200
)

Entry Parameters

Parameter	Required	Type	Description
seqdata	✓	SequenceData	Your sequence dataset created with SequenceData.
show_error_bar	✗	bool	If True, shows standard error bars for each state’s mean time. Default = True.
title	✗	str	Figure title. Default = None (no title).
x_label	✗	str	X-axis label. Default = "Mean Time (Years)". Change this to match your time unit.
y_label	✗	str	Y-axis label. Default = "State".
save_as	✗	str	File path to save the figure (e.g., "mean_time.png"). If omitted, the plot is just shown.
dpi	✗	int	Output resolution when saving. Default = 200. Use 300+ for publication quality.

What It Does

• Computes, for each state, the mean total time spent in that state across all sequences.
• Optionally computes and draws standard error whiskers for each bar.
• Sorts states by mean time (small → large) to make the chart easy to read.
• Uses your SequenceData color map so state colors match your legend elsewhere.
• Displays the plot in your environment (Notebook cell output or a window in scripts) and can save it via save_as.

Returns

None. The function draws the figure on screen, and writes it to disk when save_as is provided.

Key Features

• Intuitive “how long in each state?” summary at a glance.
• Error bars for uncertainty (toggle with show_error_bar).
• Clean defaults (light grid, readable labels) with minimal configuration.
• Publication-ready export with save_as and dpi.

Examples

1. Basic mean time plot

plot_mean_time(seqdata)

Shows the average time in each state (with SE bars) and sorts states by mean time.

2. Customize labels and hide error bars

plot_mean_time(
    seqdata,
    show_error_bar=False,
    x_label="Mean Time (Months)",
    y_label="Life-course State",
    title="Average Time Spent by State (Months)"
)

3. Save a high-resolution figure

plot_mean_time(
    seqdata,
    save_as="mean_time_by_state.png",
    dpi=300
)

Saves mean_time_by_state.png in your current working directory (or the path you specify).

R Counterpart

• Closest R function: TraMineR::seqmtplot()
• Mapping note: Direct conceptual match: mean time spent in each state.

Notes

• Units depend on your data. If your sequence time points are months, set x_label="Mean Time (Months)".
• “Standard error” here reflects variability of mean time across sequences; wider bars mean more uncertainty.

See Also

• How to Read Sequence Plots explains how to interpret and choose plot types.
• Visualization Gallery shows all plots with code.
• Visualization Tools documents shared parameters.

Authors

Code: Yuqi Liang

Documentation: Yuqi Liang

Edited by: Yuqi Liang

Translation and testing by: Sizhu Qu