Free CAS Exam 5 (Basic Ratemaking and Reserving) Reserving Data & Development Triangles Practice Questions

Reserving data and development triangles open the Estimating Claim Liabilities section of CAS Exam 5, which carries 45-55% of the exam (CAS). Questions test arranging claim data on calendar, accident, policy, underwriting, and report year bases, assembling run-off triangles for losses, claim counts, and ALAE, selecting tail factors, reading triangles as diagnostics for shifts in severity, frequency, and case reserve adequacy, and the line characteristics (long versus short tail, occurrence versus claims-made) that drive reserving behavior.

91 questions 22 easy 39 medium 30 hard 2026 syllabus

Sample Questions

Question 1 Easy
In estimating unpaid claims with the development (chain-ladder) technique, what does a tail factor represent?
Solution
C is correct. A tail factor extends development beyond the oldest maturity observed in the triangle out to ultimate, capturing the loss emergence that occurs after the latest available data point. Triangles are finite, so the tail factor accounts for development the observed link ratios cannot measure.
Question 2 Medium
An actuary subdivides a book of business into segments before estimating unpaid claims. In this context, a segment is described as 'credible' when it:
Solution
C is correct. Credibility refers to whether a segment contains enough claim volume and experience to yield statistically stable, reliable estimates. Grouping claims into homogeneous segments improves the relevance of development patterns, but each segment must still be large enough that random fluctuation does not dominate the observed factors. This is the central tension: finer segmentation raises homogeneity but can leave individual cells too thin to be credible.
Question 3 Hard
While vetting a claim-count reserve analysis, an actuary reconciles the following figures for accident year 2019 at the latest evaluation:

| Metric | Count |
|---|---|
| Reported claims | 1,050 |
| Closed claims | 1,080 |
| Selected ultimate claims | 1,040 |

Applying a reasonableness check, what should the actuary conclude?
Solution
D is correct. A basic reasonableness check on claim counts is that reported ≥ closed, because a claim must be reported before it can be closed, and that ultimate ≥ reported for an immature or mature year. Here closed claims (1,080) exceed reported claims (1,050), and selected ultimate (1,040) is below both. These relationships are internally impossible, so the figures signal a data or reconciliation error—such as duplicate closed transactions or a mismatched extract—that must be corrected before any estimate is trusted.

Guides & Articles

About FreeFellow

Jeffrey Ting, founder of FreeFellow
Jeffrey Ting
FSA, CFA · Founder

FreeFellow was built by Jeffrey Ting, a credentialed actuary and CFA charterholder who passed thirteen of the hardest exams in finance on the first attempt, and paid four-figure prep fees for every one. The learning itself was always free. The price was a moat.

So he started writing his own questions, then lessons, then mock exams, until it grew into a full prep platform covering 40 finance credentials with more than 44,000 original practice questions. The name says exactly what it is: the question bank is free, and Fellow is what you become once you pass.

01
Cost shouldn't decide who gets in.

The exam is a fair gate. A four-figure prep course is not. FreeFellow takes the second gate down, so the exam is the only one left.

02
Free should mean free.

No trial clock, no email gate, no credit card. The question bank, worked solutions, lessons, and readiness score stay free, and they are enough to pass.

03
Built by someone who sat where you sit.

He paid for the big-name courses, found nothing he respected, and built the prep he wished had existed. Not a marketing team that has never sat an exam.