Arrow Ballistics Study | 2026
FoC | Practical Effects Summary
Regression coefficients translated into practical FoC and spine changes. Lower and upper bounds are 95% uncertainty ranges; observed metric spread is the across-build standard deviation of each accuracy metric.
A note on reading this table
This table warrants a little more information on what is going on. Each row is one regression coefficient: what one model predicts about one accuracy metric (KPI) when one input changes by one unit.
- All metrics are lower-is-better. Tighter groups, less broadhead drift. A negative coefficient means the change improves the metric.
- Practical Effect Status. Detectable means the effect survives a strict Bonferroni correction across the 6 KPIs tested for that model term. Borderline means it is statistically significant on its own but does not survive that correction. No detectable effect means the model cannot distinguish the effect from zero.
- Survives Bonferroni? The boolean version of the above. Survives is the strongest claim of statistical significance available in this table.
- +5pp FoC Effect ÷ Observed Metric Spread. How big the predicted effect is compared to natural build-to-build variation. ~1.0 means the effect is as large as one standard deviation of spread across the matrix.
- Lower / Upper 95% Bound columns are the 95% confidence range for the coefficient or the translated effect. A range that crosses zero means the effect could plausibly be in either direction, which is what typically produces a Borderline or No-detectable-effect status.
Full statistical methodology lives in the Methods page.
| Strict Weight-controlled Model | Broadhead Extra Drift Past Field Point | Measured FoC (%) | 0.006 | -0.497 | 0.509 | 0.9817 | 33 | 0.458 | 1.852 | 1.0000 | No detectable effect | No detectable effect | Does not survive | 0.017 | -1.492 | 1.526 | 0.028 | -2.486 | 2.543 | 0.015 | 0.057 | -4.973 | 5.087 | — | — | — |
| Strict Weight-controlled Model | Broadhead Distance From Synthetic Aim | Measured FoC (%) | -0.026 | -0.757 | 0.705 | 0.9425 | 34 | 0.438 | 2.529 | 1.0000 | No detectable effect | No detectable effect | Does not survive | -0.078 | -2.270 | 2.114 | -0.130 | -3.784 | 3.524 | -0.051 | -0.260 | -7.567 | 7.047 | — | — | — |
| Strict Weight-controlled Model | Untorqued Broadhead Mean Radius | Measured FoC (%) | -0.407 | -0.611 | -0.202 | 0.0003 | 34 | 0.377 | 0.887 | 0.0020 | Detectable | Improves metric | Survives | -1.221 | -1.834 | -0.607 | -2.034 | -3.057 | -1.011 | -2.293 | -4.068 | -6.114 | -2.023 | — | — | — |
| Strict Weight-controlled Model | Torqued Broadhead Mean Radius | Measured FoC (%) | -0.219 | -0.393 | -0.045 | 0.0154 | 34 | 0.614 | 0.901 | 0.0925 | Borderline | Improves metric | Does not survive | -0.657 | -1.179 | -0.135 | -1.095 | -1.965 | -0.225 | -1.215 | -2.189 | -3.929 | -0.450 | — | — | — |
| Strict Weight-controlled Model | Untorqued Field Point Mean Radius | Measured FoC (%) | 0.041 | -0.015 | 0.098 | 0.1450 | 34 | 0.156 | 0.243 | 0.8701 | No detectable effect | No detectable effect | Does not survive | 0.124 | -0.045 | 0.293 | 0.207 | -0.076 | 0.489 | 0.849 | 0.413 | -0.151 | 0.977 | — | — | — |
| Strict Weight-controlled Model | Torqued Field Point Mean Radius | Measured FoC (%) | -0.051 | -0.137 | 0.036 | 0.2380 | 33 | 0.100 | 0.243 | 1.0000 | No detectable effect | No detectable effect | Does not survive | -0.153 | -0.412 | 0.107 | -0.254 | -0.686 | 0.178 | -1.045 | -0.509 | -1.373 | 0.355 | — | — | — |
| No-weight / No-speed Model | Broadhead Extra Drift Past Field Point | Measured FoC (%) | -0.189 | -0.323 | -0.056 | 0.0070 | 33 | 0.464 | 1.852 | 0.0421 | Detectable | Improves metric | Survives | -0.568 | -0.968 | -0.168 | -0.947 | -1.614 | -0.279 | -0.511 | -1.893 | -3.227 | -0.559 | — | — | — |
| No-weight / No-speed Model | Broadhead Distance From Synthetic Aim | Measured FoC (%) | -0.446 | -0.652 | -0.240 | 0.0001 | 34 | 0.428 | 2.529 | 0.0007 | Detectable | Improves metric | Survives | -1.339 | -1.957 | -0.721 | -2.231 | -3.261 | -1.201 | -0.882 | -4.462 | -6.523 | -2.402 | — | — | — |
| No-weight / No-speed Model | Untorqued Broadhead Mean Radius | Measured FoC (%) | -0.115 | -0.194 | -0.036 | 0.0059 | 34 | 0.198 | 0.887 | 0.0352 | Detectable | Improves metric | Survives | -0.344 | -0.581 | -0.107 | -0.574 | -0.969 | -0.179 | -0.647 | -1.148 | -1.938 | -0.357 | — | — | — |
| No-weight / No-speed Model | Torqued Broadhead Mean Radius | Measured FoC (%) | -0.159 | -0.203 | -0.116 | 0.0000 | 34 | 0.620 | 0.901 | 0.0000 | Detectable | Improves metric | Survives | -0.478 | -0.608 | -0.349 | -0.797 | -1.013 | -0.581 | -0.885 | -1.594 | -2.026 | -1.162 | — | — | — |
| No-weight / No-speed Model | Untorqued Field Point Mean Radius | Measured FoC (%) | 0.020 | 0.006 | 0.034 | 0.0077 | 34 | 0.166 | 0.243 | 0.0462 | Detectable | Worsens metric | Survives | 0.059 | 0.017 | 0.101 | 0.098 | 0.028 | 0.168 | 0.402 | 0.196 | 0.056 | 0.336 | — | — | — |
| No-weight / No-speed Model | Torqued Field Point Mean Radius | Measured FoC (%) | 0.008 | -0.014 | 0.031 | 0.4544 | 33 | 0.066 | 0.243 | 1.0000 | No detectable effect | No detectable effect | Does not survive | 0.025 | -0.042 | 0.092 | 0.042 | -0.070 | 0.153 | 0.171 | 0.083 | -0.141 | 0.307 | — | — | — |
| No-weight / No-speed Model | Broadhead Extra Drift Past Field Point | Nominal Spine | 0.020 | 0.012 | 0.028 | 0.0000 | 33 | 0.464 | 1.852 | 0.0001 | Detectable | Worsens metric | Survives | — | — | — | — | — | — | — | — | — | — | -1.973 | -1.191 | -2.754 |
| No-weight / No-speed Model | Broadhead Distance From Synthetic Aim | Nominal Spine | 0.006 | -0.006 | 0.018 | 0.3061 | 34 | 0.428 | 2.529 | 1.0000 | No detectable effect | No detectable effect | Does not survive | — | — | — | — | — | — | — | — | — | — | -0.597 | 0.574 | -1.767 |
| No-weight / No-speed Model | Untorqued Broadhead Mean Radius | Nominal Spine | 0.002 | -0.002 | 0.006 | 0.2607 | 34 | 0.198 | 0.887 | 1.0000 | No detectable effect | No detectable effect | Does not survive | — | — | — | — | — | — | — | — | — | — | -0.201 | 0.157 | -0.560 |
| No-weight / No-speed Model | Torqued Broadhead Mean Radius | Nominal Spine | 0.001 | -0.001 | 0.004 | 0.3614 | 34 | 0.620 | 0.901 | 1.0000 | No detectable effect | No detectable effect | Does not survive | — | — | — | — | — | — | — | — | — | — | -0.114 | 0.137 | -0.364 |
| No-weight / No-speed Model | Untorqued Field Point Mean Radius | Nominal Spine | -0.001 | -0.002 | 0.000 | 0.1738 | 34 | 0.166 | 0.243 | 1.0000 | No detectable effect | No detectable effect | Does not survive | — | — | — | — | — | — | — | — | — | — | 0.071 | 0.174 | -0.033 |
| No-weight / No-speed Model | Torqued Field Point Mean Radius | Nominal Spine | -0.001 | -0.003 | 0.000 | 0.0533 | 33 | 0.066 | 0.243 | 0.3196 | No detectable effect | No detectable effect | Does not survive | — | — | — | — | — | — | — | — | — | — | 0.146 | 0.295 | -0.002 |
| Dynamic Spine Model | Broadhead Extra Drift Past Field Point | Measured Static Spine (26") | 17.114 | 0.759 | 33.468 | 0.0409 | 33 | 0.451 | 1.852 | 0.2454 | Borderline | Worsens metric | Does not survive | — | — | — | — | — | — | — | — | — | — | -1.369 | -0.061 | -2.677 |
| Dynamic Spine Model | Broadhead Distance From Synthetic Aim | Measured Static Spine (26") | -6.880 | -30.560 | 16.799 | 0.5569 | 34 | 0.449 | 2.529 | 1.0000 | No detectable effect | No detectable effect | Does not survive | — | — | — | — | — | — | — | — | — | — | 0.550 | 2.445 | -1.344 |
| Dynamic Spine Model | Untorqued Broadhead Mean Radius | Measured Static Spine (26") | 11.007 | 4.580 | 17.434 | 0.0015 | 34 | 0.406 | 0.887 | 0.0091 | Detectable | Worsens metric | Survives | — | — | — | — | — | — | — | — | — | — | -0.881 | -0.366 | -1.395 |
| Dynamic Spine Model | Torqued Broadhead Mean Radius | Measured Static Spine (26") | 3.106 | -2.011 | 8.223 | 0.2244 | 34 | 0.617 | 0.901 | 1.0000 | No detectable effect | No detectable effect | Does not survive | — | — | — | — | — | — | — | — | — | — | -0.248 | 0.161 | -0.658 |
| Dynamic Spine Model | Untorqued Field Point Mean Radius | Measured Static Spine (26") | -1.335 | -3.158 | 0.489 | 0.1451 | 34 | 0.151 | 0.243 | 0.8708 | No detectable effect | No detectable effect | Does not survive | — | — | — | — | — | — | — | — | — | — | 0.107 | 0.253 | -0.039 |
| Dynamic Spine Model | Torqued Field Point Mean Radius | Measured Static Spine (26") | -0.400 | -3.710 | 2.911 | 0.8064 | 33 | 0.081 | 0.243 | 1.0000 | No detectable effect | No detectable effect | Does not survive | — | — | — | — | — | — | — | — | — | — | 0.032 | 0.297 | -0.233 |
| Dynamic Spine Model | Broadhead Extra Drift Past Field Point | Total Insert / FACT Weight (gr) | -0.012 | -0.033 | 0.009 | 0.2531 | 33 | 0.451 | 1.852 | 1.0000 | No detectable effect | No detectable effect | Does not survive | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Dynamic Spine Model | Broadhead Distance From Synthetic Aim | Total Insert / FACT Weight (gr) | -0.023 | -0.053 | 0.008 | 0.1414 | 34 | 0.449 | 2.529 | 0.8484 | No detectable effect | No detectable effect | Does not survive | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Dynamic Spine Model | Untorqued Broadhead Mean Radius | Total Insert / FACT Weight (gr) | 0.014 | 0.005 | 0.022 | 0.0021 | 34 | 0.406 | 0.887 | 0.0123 | Detectable | Worsens metric | Survives | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Dynamic Spine Model | Torqued Broadhead Mean Radius | Total Insert / FACT Weight (gr) | 0.003 | -0.004 | 0.010 | 0.4378 | 34 | 0.617 | 0.901 | 1.0000 | No detectable effect | No detectable effect | Does not survive | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Dynamic Spine Model | Untorqued Field Point Mean Radius | Total Insert / FACT Weight (gr) | -0.001 | -0.004 | 0.002 | 0.4654 | 34 | 0.151 | 0.243 | 1.0000 | No detectable effect | No detectable effect | Does not survive | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Dynamic Spine Model | Torqued Field Point Mean Radius | Total Insert / FACT Weight (gr) | 0.002 | -0.002 | 0.006 | 0.2749 | 33 | 0.081 | 0.243 | 1.0000 | No detectable effect | No detectable effect | Does not survive | — | — | — | — | — | — | — | — | — | — | — | — | — |
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