What type of visualization can be used to identify spikes in security incidents over time?

The type of visualization that is most effective for identifying spikes in security incidents over time is a time series graph. This type of graph specifically displays data points at successive intervals, allowing for the analysis of trends, patterns, and anomalies over a specified time period. By plotting security incidents on a time series graph, users can easily observe fluctuations, detect irregular peaks, and assess how incident frequency changes over days, weeks, or months.

Other visualizations such as bar charts can represent quantities but may not convey time-based changes as clearly as time series graphs do. Pie charts are useful for showing proportions within a single data set but do not effectively display changes over time, making them unsuitable for this purpose. Heat maps can provide insights into the intensity of incidents across different dimensions, but they do not inherently summarize the sequential chronology needed to track temporal spikes. Thus, time series graphs are the preferred choice when the focus is on analyzing the temporal dynamics of security incidents.