Bars are arranged vertically on the x-axis. Each bar represents a category or sub-category. The bar height measures the quantity (count) or sum.
• Keep bars the same color and shade when they measure the same variable (Wong, 2010).
• Use a zero baseline for the y-axis.
• Show negative values below the baseline.
• Keep the width of the bar about twice the width of the space between the bars (Wong, 2010).
Sosulski, Kristen. Data Visualization Made Simple (p. 47). Taylor and Francis. Kindle Edition.