A player radar chart (spider chart) plots multiple metrics simultaneously as a polygon — the further a point extends from the center on each axis, the better the player on that metric. The key design choice is what the outer and inner boundaries mean. The StatsBomb convention: the outermost ring represents the top 5th percentile in Europe for that metric and position; the innermost represents the bottom 5th percentile. This means a player whose shape fills the radar is elite; a player with minimal color has almost no area where they outperform league-average peers.
Design requirements: (1) normalize each metric to a percentile rank within position peer group (not all players); (2) set outer ring = 95th percentile, inner ring = 5th percentile; (3) select metrics that are independent (avoid pairs that are near-perfectly correlated); (4) include a mix of attacking and defensive metrics appropriate to the position; (5) display alongside a comparison player using a contrasting color. The radar shape should be immediately readable — "lots of color = complete player; gaps = weaknesses."
Two perfectly valid visualizations of identical data can lead to opposite conclusions depending on the reference frame. A player who shoots above average from mid-range RELATIVE TO THAT LOCATION looks good on a player-vs-location chart (useful for scouting where they're dangerous). But the same shots are below average RELATIVE TO LEAGUE-AVERAGE EFFICIENCY because mid-range shots are inherently less efficient than other shot types (useful for deciding whether to allow those shots).