Shooter Accuracy & Consistency
Where your shots actually land, and whether the problem is aim or spread. They look the same on the field and need completely different fixes.
Inputs
For each shot, record how far it landed from the center of the target.Right and long are positive,left and short are negative. A shot dead center is 0, 0.
How far off center a shot can land and still score.
Results
Shots on target
—%
What is limiting you
—
Average miss
—in
How far the group sits off center.
Group sits
—
Spread around the group
—in
Typical distance of a shot from the group's own center.
Group size
—in
Widest gap between two shots.
Hit rate if you re-aimed
—%
Shots recorded
—
How this is calculated
A shooter that misses can be wrong in two independent ways, and the fix for one does nothing for the other.
Accuracy and precision are not the same
- Bias is where the group sits. Every shot landing six inches long is a shooter that is consistent and aimed wrong. That is the good problem: adjust the angle, the speed, or the target point and every shot moves together.
- Spread is how tightly the shots cluster. Shots scattered around the target are a shooter that is aimed correctly and cannot repeat itself. No amount of re-aiming fixes it.
The page separates them by computing the average landing point and the scatter around that point, rather than around the target. Both come out as distances in inches, so comparing them is meaningful, and whichever is larger decides what to work on:
- Bias larger than spread: re-aim. The "hit rate if you re-aimed" figure is what you would get with the same shooter, perfectly aimed.
- Spread larger than bias: re-aiming barely helps. Consistency comes from steadier flywheel speed, repeatable ball position, firmer structure, and consistent compression.
With your numbers
Why the re-aimed figure is worth knowing
It puts a ceiling on what aiming can buy you. If your current hit rate is 55% and the re-aimed figure is 58%, then aiming is not the problem and three days spent on the aiming mechanism will win you three points. If it is 90%, aim is the whole story.
Recording it
Shoot from one fixed spot with the robot in a repeatable position, mark where each shot lands, and measure from target center. Ten shots is a usable start and twenty is much better. Bounces count where they first land, since that is what the shooter did.
Sources & assumptions
No VEX data is used. Everything comes from measurements you take, so there is nothing here to go stale between seasons.
The re-aimed hit rate assumes the group can be moved onto the target without changing its shape, which holds for small aim corrections and less well for large ones. Distance changes usually alter spread as well as position.
Treats a hit as landing within the target radius of center, which is a circle. A goal that is not round, or that catches shots arriving at an angle, will not match this exactly.
Save this run, and compare
Keeps what is on screen so you can change something and see both sides of the change. Saved in this browser only, never uploaded.
Save this as evidence
Collects what you entered, what came out, how it was worked out, and anything the tool flagged, with a timestamp and a version so someone else can reproduce it.
This is evidence, not a notebook entry. It deliberately does not write your problem statement, your reasoning, or your conclusion, because under RECF rules an Engineering Notebook has to be the students' own work and no tool may generate or organise its content. Take the numbers, decide what matters, and write it yourself.