A chart is an argument made with visual structure and data. Before accepting its message, identify what was measured, over what period, and for which group. The title alone may not explain these details. Read the axis labels, units, scale, and legend. Check whether an axis starts at zero and whether intervals are evenly spaced. For percentages, identify the denominator. Notice missing values and whether categories overlap. Compare the visual impression with the actual numbers. A truncated vertical axis can make a small difference look dramatic. A total can rise while a per-person measure falls if the population changes. These are not always errors, but they affect interpretation. A chart also cannot establish a causal explanation merely by showing two trends together. Practice: Inspect one chart and write a neutral sentence describing the data. Then list one conclusion the chart does not justify.