What graph should I use for comparing two groups?
For comparing two groups, a grouped bar chart places bars side by side for direct comparison. A dumbbell chart is ideal for before/after or plan-vs-actual comparisons, showing the gap between the two values.
When should I use a bar chart vs a line chart?
Use bar charts for comparing discrete categories (countries, products,
departments). Use line charts for showing trends over a continuous axis,
typically time. If your x-axis is ordered and continuous, a line chart communicates the
trajectory. If it's categorical, bars are more appropriate.
What chart do I use for percentage data?
For percentages that sum to 100%: pie chart (2-5 categories), stacked bar chart (comparing across groups), or treemap (many categories). For percentages that change over time, use a stacked area chart.
Should I ever use a pie chart?
Pie charts work well with 2-5 slices that represent parts of a whole,
especially when one category dominates. For more categories or precise comparison between
similar values, bar charts or treemaps are better. Despite their bad reputation, simple
pie charts remain effective for high-level executive summaries.
What chart shows correlation between variables?
Scatter plots show correlation between two variables. For three variables, use a bubble chart. To see correlations among many variables at once, use a correlation matrix.
How many data points do I need for a meaningful chart?
It depends on the chart type. Histograms and density plots need at
least 20-30 observations to show a meaningful distribution. Scatter plots need 10+ points to reveal patterns. Bar charts work with any number of categories. Line charts need at least 4-5 time points to show a trend.
What's the best chart for financial data?
For stock prices: candlestick charts (OHLC data). For revenue analysis: waterfall charts (showing incremental changes). For portfolio allocation: treemaps. For time-series financial metrics: line charts with area fills. For break-even analysis, try our Break-Even Chart Generator.
What chart for survey data?
For single-response questions: bar chart or horizontal bar chart for ranked results. For Likert scale data: stacked bar chart. For comparing survey results across demographics: grouped bar chart. For "select all that apply" questions: horizontal bar sorted by frequency.
What chart for showing outliers?
Box plots explicitly mark outliers as individual points beyond the whiskers. Scatter plots make outliers visible as isolated points far from the cluster. Histograms show outliers as isolated bars in the tails.