r2rtf
The clinical-report table engine learned Chinese, then learned to leave RTF entirely
Comparison · Analytics
gsDesign2 vs simtrial
A side-by-side editorial comparison of gsDesign2 and simtrial — release velocity, themes, recent moves, and the top alternatives to consider.
Shared themes:clinical-trialsgroup-sequentialpharmaverse
gsDesign2 vs simtrial: at a glance
What is gsDesign2?
Group sequential design tooling that now monitors for harm, not just efficacy and futility.
gsDesign2 is the Merck-authored R package for group sequential clinical trial design under non-proportional hazards, and it has spent the last two years filling in the statistical surface its predecessor gsDesign established. Recent releases added conditional power (gs_cp, gs_cp_npe), sequential p-values, risk-difference designs with minimal risk weighting, and boundary updates from blinded interim estimates. Version 1.2.0 adds harm boundaries across the AHR and NPE design and power functions, wired through every summary and table export path.
What is simtrial?
A fixed-design trial simulator grew a pluggable test framework, then spent a year proving the numbers
simtrial simulates time-to-event clinical trials and applies the tests used to analyse them — logrank, weighted logrank, MaxCombo, RMST, milestone. The 0.4.0 release turned it from a fixed-sample simulator into a group sequential one and standardised every test behind a common output contract, and the releases since have been about making that machinery correct and fast enough to run at scale. Version 1.0.0 arrived in June 2025 with the API settled and three vignettes explaining both the one-call and build-it-yourself paths.
gsDesign2 vs simtrial: editorial side-by-side
gsDesign2
3.8ANALYTICS
Group sequential design tooling that now monitors for harm, not just efficacy and futility.
◆ Current state
gsDesign2 is the Merck-authored R package for group sequential clinical trial design under non-proportional hazards, and it has spent the last two years filling in the statistical surface its predecessor gsDesign established. Recent releases added conditional power (gs_cp, gs_cp_npe), sequential p-values, risk-difference designs with minimal risk weighting, and boundary updates from blinded interim estimates. Version 1.2.0 adds harm boundaries across the AHR and NPE design and power functions, wired through every summary and table export path.
◆ Where it's heading
The package is converging on parity with gsDesign while extending past it — each release either closes a gap against the older package or adds a boundary type gsDesign never had. A visible second track is output plumbing: every new statistical feature now arrives already threaded through summary(), gs_bound_summary(), as_gt(), and as_rtf(), which is what regulatory submission work actually consumes. Performance work is steady but secondary, with gs_design_ahr() roughly 2x faster in 1.1.9.
◆ Prediction
Expect the harm boundary work to propagate into the WLR and risk-difference design families, which are the two design branches 1.2.0 left untouched, along with a vignette bridging harm boundaries to the remaining gsDesign test types.
simtrial
0.0ANALYTICS
A fixed-design trial simulator grew a pluggable test framework, then spent a year proving the numbers
◆ Current state
simtrial simulates time-to-event clinical trials and applies the tests used to analyse them — logrank, weighted logrank, MaxCombo, RMST, milestone. The 0.4.0 release turned it from a fixed-sample simulator into a group sequential one and standardised every test behind a common output contract, and the releases since have been about making that machinery correct and fast enough to run at scale. Version 1.0.0 arrived in June 2025 with the API settled and three vignettes explaining both the one-call and build-it-yourself paths.
◆ Where it's heading
Post-1.0 the work is almost entirely statistical correctness and speed, and it is concentrated in sim_gs_n(): one-sided efficacy bounds, stratified targeted-event cut dates, a helper that derives cuttings straight from the design object. Performance moves in one direction throughout — dplyr replaced by data.table, foreach combination replaced by manual assembly, parallelisation added to sim_fixed_n() — because simulation-based operating characteristics are only useful if you can afford enough replications.
◆ Prediction
The recent fixes cluster on stratified and group sequential paths, so the next release most likely continues there rather than adding a new test type. The cut_from_design() helper suggests tighter coupling to gsDesign2 design objects is the direction of travel.
Alternatives to gsDesign2 and simtrial
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 gsDesign2 or simtrial.
DoseFinding
New stewardship at openpharma, then two releases adding the methods MCP-Mod was missing
webmockr
The stubbing library added httr2 support, then spent a year cutting itself free of everything else
crul
crul took mocking back from webmockr and made it a property of the client itself
dendroNetwork
Six releases, six identical bodies — the feed carries the package abstract instead of release notes
chattr
chattr deleted every LLM integration it had written and outsourced the lot to ellmer
See all gsDesign2 alternatives → · See all simtrial alternatives →
Recent activity from gsDesign2 and simtrial
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 8d agogsDesign2Harm boundaries land in AHR and NPE group sequential designs ⚡
- 1mo agogsDesign2Conditional power, sequential p-values, and minimal risk weighting
- 5mo agogsDesign2gs_design_ahr() can output spending time
- 8mo agosimtrialOne-sided efficacy bound and stratified cut date corrected
- 8mo agogsDesign2S3 class refactor and futility boundary vignette
- 11mo agosimtrialsim_gs_n moved to data.table; stratified design example added
- 11mo agogsDesign2h1_spending for WLR power, info_scale across fixed designs
- 1y agogsDesign2WLR design spending default corrected to information fraction
- 1y agosimtrial1.0.0 settles the wlr interface and documents both simulation paths
- 1y agosimtrialMilestone Z-score denominator corrected; parallel sim_fixed_n arrives
- 2y agosimtrialChecks pass without Suggests dependencies
- 2y agosimtrialRMST and milestone tests, plus a user-definable cut and test framework ⚡
Frequently asked questions
What is the difference between gsDesign2 and simtrial?
Both compete on the same themes — clinical-trials, group-sequential, pharmaverse — within Analytics. gsDesign2 is currently shipping more aggressively (velocity 3.8 vs 0.0), with 1 editorial sparks in the last 30 days against 0. See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.
Is gsDesign2 better than simtrial?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. gsDesign2 is currently shipping more aggressively (velocity 3.8 vs 0.0), with 1 editorial sparks in the last 30 days against 0. For your specific use case, the alternatives sections above list other Analytics products to evaluate alongside.
What are the best alternatives to gsDesign2?
Top gsDesign2 alternatives in Analytics are ranked by recent ship velocity. Browse the "gsDesign2 alternatives" section above for the current picks, or visit /alternatives/gsdesign2 for the full list with editorial commentary on each.
What are the best alternatives to simtrial?
Top simtrial alternatives in Analytics are ranked by recent ship velocity. Browse the "simtrial alternatives" section above for the current picks, or visit /alternatives/simtrial for the full list with editorial commentary on each.