Where Mully's advice comes from
Most golf AI lets you assume it made the advice up. Mully doesn't work that way. Every benchmark it cites traces to a named, published source, and here is the whole tree. If a number isn't backed by one of these, Mully doesn't use it.
New to the numbers? Read the metrics catalog →
Primary authorities
Instrument makers, governing bodies, and published research. Every numeric fact and ball-flight law traces here.
Optimal launch angles, tour averages, optimizer standard assumptions. Spin-rate tour averages, optimizer spin, amateur Combine spin by level. Smash factor by club, tour averages, amateur Combine smash by level. Spin axis sign convention, near-straight window, curvature by yardage. Ball-flight laws: face angle = start direction, face-to-path = curvature.
Strokes-gained framework, putting make %, up-and-down %, long-game dominance of scoring.
Shot databases
Large shot-tracking datasets from named companies. The per-handicap benchmarks come from these.
Instruction
PGA-credentialed coaching whose drill methodology and feel cues Mully can draw on. Vetted for credential, not social-media tips.
PGA pros Piers Ward + Andy Proudman. TPI-certified, launch-monitor-validated fault diagnosis and drill prescriptions. Tour-player collaborations (Russell Henley, Tommy Fleetwood).
Feel-based instruction with biomechanics grounding. Mnemonic teaching system (G.R.I.P.S., S.W.E.E.P.) for on-course recall. Best for simplifying technical fixes into one-cue feels.
Hogan's 1957 Five Lessons (grip, stance, backswing, downswing, integration). Sequential-fundamentals method — master each block before moving forward. Surfaced via Christo Garcia's Classic Golf Swing channel.
Mike Granato + Shaun Webb + Kevin Sprecher. 3D motion capture (GEARS), force plates, TrackMan analysis. Best for understanding the biomechanical 'why' behind a fault — debunks 10+ common swing myths with data.
A few of the actual yardsticks
Real reference figures Mully reads your numbers against — baselines, not targets it forces on you.
- Driver
PGA Tour avg: launch ~10.4 deg, spin ~2,545 rpm, smash ~1.49. Well-struck target smash ~1.50. Optimizer (~94 mph club speed, level attack): launch ~13.6 deg, spin ~2,772 rpm. Optimal launch/spin must be fit to the player's club speed and attack angle.
TrackMan - 6-iron
PGA Tour avg: launch ~14.0 deg, spin ~6,204 rpm, smash ~1.39.
TrackMan - Pitching wedge
Target smash ~1.25; optimizer spin ~8,408 rpm at ~72 mph club speed.
TrackMan - Where strokes are won
Strokes gained splits scoring into Off-the-Tee, Approach, Around-the-Green and Putting. The long game, especially approach play from ~150-200 yards, correlates most strongly with scoring; 'drive for show, putt for dough' is overstated. Added driver distance is worth roughly +0.75 strokes per extra 20 yards for a strong player.
Mark Broadie (Every Shot Counts) - Greens in regulation by handicap
GIR: scratch ~56% (~10 greens/round); 10-HCP ~34%; 18-HCP ~23% (~4 greens). Approach proximity: scratch ~26 ft on GIR approaches (~44 ft all approaches); 18-HCP ~35 ft.
Arccos - Fairways and driving distance by handicap
Fairways hit: scratch ~51%. Driving distance: 0-5 HCP ~243 yds, 10-HCP ~227 yds, 16-20 HCP ~209 yds.
Arccos