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.
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
These are real reference figures Mully reads your numbers against. Reference 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
Advice you can trace is advice you can trust
Every read Mully gives you inside the app carries the same sourcing. Drop in one export and see it for yourself.