CAS Exam Errata
We always hated seeing errors in study material when taking exams, so we check our content to ensure you are practicing with the most accurate actuary exam questions possible. If you do see a mistake, check out the up-to-date errata below for any corrections.
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If you spot an error in the study material, please send us a message so that we can correct the error and document it here for others.
Errata by Exam
Study Guide
We uploaded a fresh version of the guide on 7/6/26 to address some typos. We recommend downloading a new copy of the guide. Alternatively, you can find the material changes below with a 7/6/26 date.
WM Ch. 4 – (7/6/26) – On the bottom of page 27, it should say “remaining 75% of the total exposure…earned in…”
WM Ch. 4 (7/6/26) – On the top of page 31, it should say “in-force exposures are 4.00 on 6/15/11.”
WM Ch. 5 (7/6/26) – On the bottom of page 38, it should say “remaining 75% of the total premium…earned in…”
WM Ch. 6 (7/6/26)
- On the top of page 64, in the third bullet under RY aggregation, it should say “…are reported during the year”
- On the bottom of page 82, it should say that the AY 2002 losses are $1,000,000 and $1,500,000 at 15 months and 27 months, respectively
- On page 75, under “Minimum Benefit,” it should say that the current benefit for the < 50% bucket is $3,500. Under “Maximum Benefit,” it should say that the current benefit for the > 150% bucket is $11,000.
WM Ch. 6 (7/6/26) – On the bottom of page 82, it should say that the AY 2002 losses are $1,000,000 and $1,500,000 at 15 months and 27 months, respectively
WM Ch. 8 (7/6/26) – On the top of page 183, the credibility weighted formula should show (1-0.30), not (1-0.70)
Friedland Ch. 3 (7/6/26) – At the bottom of page 278, when discussing deductible for third-party lines, it should say that “claim payments are made to injured parties prior…”
Cookbook
IRIS Ratio 3 – (7/17/26) – The definition of “Net” should be Direct + Assumed – Ceded.
Study Guide
Taylor & McGuire (7/7/26) – On page 395, at the end of the Delta Method section, we updated the wording around the Cookbook to align with the updated recipe.
Cookbook
Meyers – SCC Model (7/19/26) – The formula shown on row 57 should say “0.120^2/2.” This changes the row 59 to C_4,ult ~ lognormal(10.885, 0.042) + 3,967.
Practice Problems
Meyers – RF 12 (7/19/26) – In cells R16:R18, the formulas were pointing to some false cells. The problem has been fixed and reposted.
Study Guide
As we wrapped up the new Chalk videos, we made a few changes in the guide. You can find these 7/6/26 changes below. You can also download an updated version of the guide on the course.
Chalk Ch. 3 (7/6/26) – At the top of page 242, the displayed formula for pseudo-R2 should be sum(ex_i*y_i)/sum(ex_i).
Chalk Ch. 5 (7/6/26) – At the bottom of page 275, it should say that the fitted relativities are monotonically increasing as we move from good to bad pilot qualities.
Chalk Ch. 6 (7/6/26) – At the bottom of page 293, under the low credibility/no information bullet it should say that the encoded value is pulled close to the complement (0 or 1)
Chalk Ch. 7 (7/6/26) – At the bottom of page 300 and top page 301, the discussion around credit score was altered to make it clear the score and its components are included in the model
Chalk Ch. 8 (7/6/26) – At the bottom of page 318, the weights should be 0.014 and 0.759 since they already reflect exposures*frequency
Chalk Ch. 9 (7/6/26) – At the top of page 331, the words “since permutation-based feature importance is model agnostic” were removed from the third advantage
Update (7/2/26): Currently there is no errata for the fall sitting.