The sideline chains used in all NFL games are a little more tricked-out with color and plastic coverings, but they are essentially identical to the ones used when I played high school football fifty years ago.
In the extreme high tech world of the NFL, this analog anomaly is still around because nothing has been found to improve on it.
“There must be a better way,” said Pat Summerall, the longtime N.F.L. player and broadcaster. “Because games are decided, careers are decided, on those measurements.”
Ideas have come and gone, but "inventors like Alan Amron, a 60-year-old from Long Island, plan their extinction."
"In 2003, with the help of Summerall, Amron presented a sophisticated laser system to the competition committee."
"Using lasers permanently mounted into stadium lights, a green line — visible to players, coaches and fans in the stadium, and to television viewers — would be projected onto the field to mark the line for a first down."
"Amron said it would be accurate to within a sixteenth of an inch."
I'm sure we will soon see a digital alternative to chains, but the game will lose one of its most dramatic rituals:
"[An] official protectively holds the ball against the ground, because precision is suddenly important. The chains arrive from the sideline. An official slowly pulls the chain taut. Breaths are held."
“When we measure, we make sure the players are clear so that TV can get a good shot of the actual measurement,” [Mike] Pereira [Director of NFL Officials] said."
"Suspense would be lost if every first down were determined instantly."