← Back to home
Comparison · Analytics

hardhat vs rstanarm

A side-by-side editorial comparison of hardhat and rstanarm — release velocity, themes, recent moves, and the top alternatives to consider.

hardhat vs rstanarm: at a glance

Featurehardhatrstanarm
SectorAnalyticsAnalytics
Velocity score0.00.0
Sparks · 30d00
Top themestidymodels, r-stats, machine-learning, infrastructurebayesian, stan, regression-models, dependency-migration
Last editorial update4h ago1h ago
WebsiteVisit →Visit →

What is hardhat?

hardhat keeps adding the contracts tidymodels needs next

hardhat is the infrastructure layer under tidymodels, defining the preprocessing and extraction contracts other packages implement. Its releases read as a list of new generics and vector classes: extract_postprocessor(), extract_fit_time(), extract_tailor(), and a quantile_pred() class for quantile-regression output. The newest release is narrow warning and missing-value handling in mold().

Read the full hardhat trajectory →

What is rstanarm?

rstanarm is community-maintained now, tracking Stan and lme4 rather than adding models.

2.32.2 is entirely infrastructure and dependency work: formula machinery migrated from lme4 to reformulas, `r_eff` no longer computed for loo by default, the Stan R packages repo replaced by R-Universe, rstantools adopted to fix build and export errors, and CRAN NOTE cleanups — contributed largely by four first-time contributors. 2.32.1 and 2.26.1 follow the same pattern, tracking rstan syntax and adding `posterior::as_draws()` support. The last release with substantive modelling content is 2.21.1, which changed how default priors are determined and flipped `autoscale` to FALSE outside default priors.

Read the full rstanarm trajectory →

hardhat vs rstanarm: editorial side-by-side

H
hardhat
ANALYTICS
0.0

hardhat keeps adding the contracts tidymodels needs next

◆ Current state

hardhat is the infrastructure layer under tidymodels, defining the preprocessing and extraction contracts other packages implement. Its releases read as a list of new generics and vector classes: extract_postprocessor(), extract_fit_time(), extract_tailor(), and a quantile_pred() class for quantile-regression output. The newest release is narrow warning and missing-value handling in mold().

◆ Where it's heading

Each addition here lands ahead of a user-facing feature elsewhere in tidymodels — the postprocessor and tailor generics precede the postprocessing workflow, quantile_pred() precedes quantile prediction in parsnip. The package's own surface stays deliberately small and its cadence follows what the rest of the stack is about to need.

◆ Prediction

Expect further extraction generics and prediction-type classes as tidymodels builds out postprocessing, with hardhat's own API remaining thin.

R
rstanarm
ANALYTICS
0.0

rstanarm is community-maintained now, tracking Stan and lme4 rather than adding models.

◆ Current state

2.32.2 is entirely infrastructure and dependency work: formula machinery migrated from lme4 to reformulas, `r_eff` no longer computed for loo by default, the Stan R packages repo replaced by R-Universe, rstantools adopted to fix build and export errors, and CRAN NOTE cleanups — contributed largely by four first-time contributors. 2.32.1 and 2.26.1 follow the same pattern, tracking rstan syntax and adding `posterior::as_draws()` support. The last release with substantive modelling content is 2.21.1, which changed how default priors are determined and flipped `autoscale` to FALSE outside default priors.

◆ Where it's heading

The package has moved from feature development into ecosystem maintenance, and the contributor list shows why it survives: outside developers keep it compiling against a moving Stan, lme4 and CRAN. The `as_draws()` support and the reformulas migration both point the same way — rstanarm increasingly consumes shared infrastructure (posterior, reformulas, rstantools) instead of carrying its own.

◆ Prediction

Expect the next release to track another upstream change — rstan, reformulas or CRAN policy — rather than add model families. The pre-fit model surface looks settled.

Alternatives to hardhat and rstanarm

Other Analytics products tracked by Sparkpulse, ranked by recent ship velocity. Each card links to a full editorial trajectory and lets you pivot into a head-to-head comparison with either hardhat or rstanarm.

See all hardhat alternatives → · See all rstanarm alternatives →

Recent activity from hardhat and rstanarm

Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.

  1. 4mo agohardhatmold() warning and quantile missing-value fixes
  2. 10mo agorstanarmrstanarm 2.32.2 migrates formula machinery to reformulas
  3. 11mo agohardhatextract_tailor() generic added
  4. 1y agohardhatquantile_pred() class for quantile regression output
  5. 2y agohardhatextract_postprocessor() and extract_fit_time() generics
  6. 2y agohardhatDocumentation topic renamed at CRAN's request
  7. 2y agorstanarmrstanarm 2.32.1 fixes unit_vector error, enables LTO
  8. 2y agorstanarmrstanarm 2.26.1 adopts new rstan syntax and as_draws()
  9. 3y agohardhatMulti-outcome prediction helpers and one-hot factor encoding
  10. 4y agorstanarmrstanarm 2.21.3 fixes loo() and adds stan_jm offsets
  11. 6y agorstanarmrstanarm 2.21.1 changes default prior behaviour

Frequently asked questions

What is the difference between hardhat and rstanarm?

They serve adjacent needs but don't currently overlap on shipped themes. hardhat and rstanarm are shipping at a similar cadence (velocity 0.0 vs 0.0, both within Sparkpulse's "active" band). See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.

Is hardhat better than rstanarm?

Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. hardhat and rstanarm are shipping at a similar cadence (velocity 0.0 vs 0.0, both within Sparkpulse's "active" band). For your specific use case, the alternatives sections above list other Analytics products to evaluate alongside.

What are the best alternatives to hardhat?

Top hardhat alternatives in Analytics are ranked by recent ship velocity. Browse the "hardhat alternatives" section above for the current picks, or visit /alternatives/hardhat for the full list with editorial commentary on each.

What are the best alternatives to rstanarm?

Top rstanarm alternatives in Analytics are ranked by recent ship velocity. Browse the "rstanarm alternatives" section above for the current picks, or visit /alternatives/rstanarm for the full list with editorial commentary on each.