But ratios of what? A simple ratio of three attacking soldiers vs 1 defending soldier is too narrow and dangerously misleading, as Russia’s invasion of Ukraine is demonstrating.

Soldier equivalents of a number of other factors apply, also, and “force ratios” of the following, at the least, must be included in developing the operational force ratio:

• quality of soldier training
• quality of commanders, officers, and NCOs
  • their ability to function in fluid, information-foggy environment
  • quality of intel available to them
• quality and condition of equipment
• technology of equipment
• impact of other avenues of attack
  • cyber
  • space
  • propaganda
• what’s being defended
  • home territory from invader
  • invader territory from counterattacking defender
• who’s defending
  • attacked nation defenders
  • attacking nation now defending
  • attacker position on invaded territory
  • attacker position in attacking nation’s territory
• who’s attacking
  • defending nation against attacker’s position in attacked nation
  • defending nation against attacker’s position in attacker’s nation

All of that disregards the nature of the terrain being defended/attacked, but terrain merely informs the level of required force ratio: 3:1 to 7:1, the upper bound of what’s nominally considered attackable or worth the cost to attack, or somewhere in between.

It may be that a 3:1 ratio of attackers to defenders is a valid minimum ratio for a successful attack. However, all of these factors have to be converted into their own weights on force-on-force—however hazily the estimated conversions might be—and included in the ratio calculations.

It’s especially critical, too, that cold-blooded, wholly objective estimates of the quality of one’s own soldiers vs the enemy’s be made. “The enemy is ten feet tall,” or “We are,” serve only to get friendly soldiers killed, and the attack likely defeated, regardless of the other factors incorporated into the final force-on-force estimate.