A trend chart is a graphical representation of time series data in the form of plotted points connected by line segments which represent recorded data and baseline data. The resulting line of connected segments extends to the right. The y axis represents a metric. The x axis represents the time variable. The baseline connected line is presented for comparison against the connected line of the recorded data.
Trend charts can be employed for various types of analysis. They provide information about data in sequence over time, and are commonly employed for financial metrics, but they are also useful in various types of engineering, project management analysis, and other applications. An example of their usage is tracking monthly performance of sales. Another example would be examining patterns in the stock market. They can also be used to monitor the readings of industrial equipment to ensure the equipment is performing to standard.
Trend charts suffer from limitations in scope. They can only be used for small data sets, and only so many baselines can be presented. If the user attempts to use trend charts outside of this defined scope, the chart is overloaded and difficult to quickly interpret, or trends become difficult to find.
Trend charts are also limited by the care and attention to detail that is required to create a viable, meaningful chart. These charts, unlike many others, cannot be quickly and easily generated. The user must pay attention to the metric ranges to ensure they agree with the stated purpose of the chart. They must also ensure that the scale allows a specific type of trend to be seen, which may require substantial experimentation; and it may not be possible in many situations to generate a trend chart with meaningful data.