RERUN
Claim 22

Does a 1991 model get the timing of a forest pest right?

Independent rebuild

A 1991 study gave one number for how a forest pest develops as the season warms. The Lab retraced it: ✓ same result.

Why not the authors' own code?

The original analyses from 1986 and 1991 were written for SAS and GLIM, older statistics software the Lab can't run. SAS is also paid. This claim runs a rebuild in R by another researcher, published in a peer-reviewed journal.

See the rebuild, which includes the original code

Spruce budworm defoliates millions of hectares of forest, so predicting its timing decides when to act.

What this result means

We test-ran this code once while building the Lab, so we've already seen one result. Its official run came after forecasting closed.

We test one thing: does this code and data give this number? That's not the same as the science being right. The forecast price never changes the verdict.

See the proof
-0.0457model setting, the paper says. Counts if between -0.046157 and -0.045243.
Where the number comes fromOriginal -0.0457, logitTable 2 of the ReScience C article

The exact claim as posted

A timing model for a forest pest: Candy's 1991 slope of -0.0457

Candy (Environmental Entomology, 1991) modelled how spruce budworm, a forest pest, moves through its life stages as the season warms. He reports a slope of -0.0457 for the cumulative logit model. This re-runs an independent R replication by Boersch-Supan, published in ReScience C, on the same counts.

RERUNCLAIM #0022

Does a 1991 model get the timing of a forest pest right?

Measured in
model setting
Paper says
-0.0457
Counts if
-0.046157 to -0.045243
Lab got
-0.045599
VerdictNumbers check out
c4a9b60c770317e5f7ecNov 09, 2026

This result is final

Paper said -0.0457. We got -0.045599.

The code and data produced the same result. That doesn't prove the study's method is right.

This slip is the Lab's .

✓ Verified on NEAR. See the contract's history

See the full receipt

  1. People forecast
  2. Forecasting ends
  3. The Lab retraces it
  4. Verdict posted, open to challenge
  5. Winners collect

What we didn't check

  • Whether the sample was fair or large enough.
  • Whether test data leaked into training or tuning.
  • Whether the result holds on new data.
  • Whether the study's method was the right one for its question.

Reading how the odds moved…

The evidence

See the full receipt

How much evidence is behind this?

Each step is a tougher test. Only the first one decides who wins the market.

  1. 1. ✓

    The Lab's retrace of the code and data named in the claim

    The Lab retraced the code and data and got a number inside the claim's range. YES wins.

  2. 2. –

    Stress test: does the number depend on luck?

    Fetching the extra runs…

  3. 3. –

    Rebuilt from the description (experimental)

    Fetching the AI's rebuild…

Coming next: a data-leakage check, for the same rows in training and test data, and a maths check on the statistics a paper reports. Neither has run on this claim.

Even all three steps can't prove the science is true. They show how well this result stands up to checking.

Verified

Your browser just re-checked these itself, so you don't have to trust this site.

Checking…

What the Lab retraces

Source
https://doi.org/10.5281/zenodo.5006005
Replication: P. H. Boersch-Supan. Original: S. G. Candy., CC-BY-4.0
Code, at this exact version
https://github.com/pboesu/replication_candy_1991
commit 98329d447ef025c260879f28316015fc0b24fb08
Commands
r4.4
$ mkdir -p /work/.rlib
$ Rscript --vanilla -e "install.packages(c('gtools','VGAM','ordinal'), lib='/work/.rlib', repos='https://cloud.r-project.org')"
$ Rscript --vanilla -e "source('code/02_fit_candy_1991_models.R'); cat(sprintf('slope %.6f\n', logit_cm_candy_nll\$par[7]))" > rerun_output.txt
Where the result is read
rerun_output.txt using regex slope (-?[0-9.]+)
Data files
None
Limits
2 CPU, 2 GB, 15 minutes
c4a9b60c770317e5f7ec3aacbac1513bd2f133958bb226d29762fa2a39ae86d1
Show the claim exactly as stored on the blockchain
{"artifact":{"commit":"98329d447ef025c260879f28316015fc0b24fb08","data":[],"entrypoint":"Rscript --vanilla -e \"source('code/02_fit_candy_1991_models.R'); cat(sprintf('slope %.6f\\n', logit_cm_candy_nll\\$par[7]))\" > rerun_output.txt","output":{"extractor":{"expr":"slope (-?[0-9.]+)","type":"regex"},"path":"rerun_output.txt"},"repo_url":"https://github.com/pboesu/replication_candy_1991","runtime":"r4.4","setup":["mkdir -p /work/.rlib","Rscript --vanilla -e \"install.packages(c('gtools','VGAM','ordinal'), lib='/work/.rlib', repos='https://cloud.r-project.org')\""]},"metric":{"comparison":"within_tolerance","name":"slope of the cumulative logit model","reported_value":"-0.0457","tolerance":{"type":"rel","value":"0.01"}},"private_data":null,"resources":{"cpu":2,"max_minutes":15,"mem_gb":2},"source":{"authors":"Replication: P. H. Boersch-Supan. Original: S. G. Candy.","doi":"10.5281/zenodo.5006005","license":"CC-BY-4.0","type":"paper","url":"https://doi.org/10.5281/zenodo.5006005"},"statement":"Candy (Environmental Entomology, 1991) modelled how spruce budworm, a forest pest, moves through its life stages as the season warms. He reports a slope of -0.0457 for the cumulative logit model. This re-runs an independent R replication by Boersch-Supan, published in ReScience C, on the same counts.","title":"A timing model for a forest pest: Candy's 1991 slope of -0.0457","version":1}

Community notes

Notes are people's own words, kept on the blockchain. They never change a verdict, and the Lab's AI never reads them. Posting costs a little NEAR for storage, and what isn't used comes back.