Marty puts on the jacket that Doc gave him and it clearly doesn’t fit.  The sleeves are way too long and the pocket flaps are hanging out.  As Doc runs back, there’s a beeping noise.  Doc presses a blinking button at the bottom of the jacket and an electronic voice says, “Size adjusting. Fit.”  The pocket flaps and sleeves of the jacket are pulled up and appear to fit properly.

The movie suggest that the jacket Marty is wearing will adjust to fit multiple sizes.  However, only the sleeve length changes…and the pocket flaps for some reason.  The length of the jacket never changes nor does the width.  If Doc tried on the jacket, the arms might fit fine but it would be too short.  If an overweight man tried on the jacket, he’d never be able to zip it shut.

Considering that the body of the jacket will only fit people up to a certain size, it’s strange that the maximum sleeve length is so long.  You’d think the manufacturer would take at least six inches off the sleeve to save costs and still be able to fit any human arm length.

Marty and Marty Jr. appear to be the only people in the movie wearing size-adjusting jackets.  (Doc, Biff, Griff, Griff’s gang, and the McFly family certainly show no sign of any excess fabric in their clothing that got pulled up to fit properly.)  It appears that in Hill Valley of 2015, automatic sized clothing hasn’t quite caught on.

It may not be widespread in Hill Valley, but this clothing technology doesn’t exist at all in the real 2015.

During the production of the movie, the crew pulled wires to simulate the clothing adjustment.  This is why Michael J. Fox never moves from that spot until the camera cuts away.

Prediction Accuracy: Failed