Landslide elections are becoming more common in open House races

Three-cycle rolling average number of close and landslide victories in open U.S. House elections

Line chart of the number of close victories and landslide victories in open U.S. House elections, where the number of landslide victories has doubled since 1980.

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Note: Close victories are defined as those where the margin of victory was under five percentage points, while landslide victories are those where the margin of victory was over 15 percentage points.

Source: MIT Elections Lab and FEC candidate data