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Gaming & Esports Medium #rng#prd#design

Random vs Pseudo-Random Distribution

True RNG produces streaks; PRD smooths them out for fairer-feeling combat.

A free, animated random vs pseudo-random distribution you can read here or embed on any website, from Scrollchart.

Random vs Pseudo-Random Distribution

Random vs Pseudo-Random DistributionTrue 25% RNG produces long miss streaks. PRD-25% concentrates gaps near the mean of 3.0%5%10%15%20%P(k misses before hit)Misses before next hit (k)01234567891011121314True RNG: 1-in-18chance of 10+ miss streakPRD peak: 0 misses19% of hits land immediatelyHow PRD worksInitial hit chance: CEach miss: +C to chanceOn hit: resets to Cp=25%, C = 0.0625True RNG max streak:unboundedPRD guaranteed hitby miss k=16hard cap: 16 missesTrue 25% RNGPRD-25% (Dota-style)

Distribution of misses-between-hits for true 25% chance vs PRD-25%. Dota-style PRD eliminates frustrating long streaks.

Good for

  • Game-design articles explaining why Dota, League, and other MOBAs use PRD instead of true RNG for proc-based abilities
  • Combat-balance deep-dives comparing the psychological impact of streak variance versus smoothed distributions
  • Developer postmortems on ability design, crit systems, and how hit-chance perception affects player satisfaction

Source & accuracy

This random vs pseudo-random distribution is an editorial illustration built to represent the concept accurately. Where it shows figures, they are typical or representative values chosen to make the relationship clear, not a single underlying dataset. The diagram and its explainer are reviewed and maintained centrally, and updated over time as understanding improves.

True RNG produces frustrating streaks

True random number generation means every roll is independent. Flip a coin 10 times, you might get HHHHHHTTTTT (six heads, then six tails). Mathematically fair, psychologically brutal. In combat, true RNG can produce a critical hit streak that one-shots you, or a drought where you miss six times in a row. Players experience this as unfair even when the probabilities are honest. This is why professional games often abandon true RNG for a smoother alternative.

Pseudo-random distribution evens the variance

Pseudo-random distribution (PRD) guarantees that if your critical strike chance is 20%, you will get a crit within every 5 attacks on average, with no droughts longer than 10 or streaks longer than 3. PRD requires tracking internal state (how many actions since the last crit), but it creates more predictable feel and less frustration. RPGs like Dota 2 use PRD for crits and dodges; roguelikes often use true RNG for replayability and surprise. Neither is objectively better, but PRD makes combat feel fairer, which matters more than actual fairness in single-player games.

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Reference

What this is
A free, embeddable, animated random vs pseudo-random distribution for any website.
Who uses it
Gaming blogs & wikis.
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Copy one line of HTML. No signup. No watermark. Works in WordPress, Webflow, Ghost, Substack, plain HTML.
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License
Free forever. Editorial explainer text included; updated centrally over time.

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Frequently asked questions

Where can I get a free animated "Random vs Pseudo-Random Distribution" for my website?
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