Card Ladder Value Algorithm (For Graded Cards Without a Ladder Profile) – Card Ladder

This document explains how Card Ladder Value (CLV) is calculated for graded cards that do not have Ladder Profiles.

Here's an example of a card with a Ladder Profile: 1996 Topps Chrome #138 Kobe Bryant PSA 10.
Here's an example of a sale of a graded card without a Ladder Profile: 1996 Pacific Power Platinum #PP-6 Kobe Bryant PSA 8.

At the outset, please note that cards with Ladder Profiles are treated differently. Their CLV calculation is described here—in "Section III. Index-Suggested Price Modeling." In brief: for cards with Ladder Profiles, their CLV is calculated by simply multiplying 1) the "last sold price" by 2) the change in the player's or character's index since the sale.

Card Ladder can use this simplified method for Ladder Profile cards because each sale of a Ladder Profile card has been reviewed by a member of Card Ladder’s research team. For graded cards without Ladder Profiles, however, individual sales do not always receive the same level of researcher review. Accordingly, Card Ladder applies additional safeguards, including outlier detection, before calculating CLV.

With that preamble in mind, the methodology for calculating CLV for graded cards without Ladder Profiles is set forth below.

1. Identification

First, identify the exact graded card by determining:
1. the card
2. the grade
3. the grading company
That exact card + grade + grader is the basis for generating the CLV.

2. Limits + Apply Exclusions

Up to 1,000 sales of the graded card are retrieved.
Sales from flagged sellers are excluded.

3. Choosing The “Representative Sale”

Now, identify the sale that will serve as the "representative sale."
- Step 1: identify “recent sales.”
  - Gather all sales of the graded card within the last 6 months.
  - If there are more than 10 sales in the last 6 months, then only gather all sales within the last 3 months.
- Step 2: if the set of “recent sales” is larger than 3, then use IQR. (IQR stands for InterQuartile Range—a statistical method that identifies unusually high or low sale prices relative to the rest of the data set).
  - Apply IQR—
    - Create the IQR data set: remove all “recent sales” except the newest 25. If there are fewer than 25, then that is the IQR data set.
    - Apply Tukey IQR rule to remove outliers from the IQR data set.
      - The Tukey IQR rule follows. It uses linear quartiles.
        
        Calculate Q1 and Q3.
        
        Set IQR = Q3 − Q1.
        
        Remove sales below Q1 − (1.5 × IQR) or above Q3 + (1.5 × IQR).
    - After this filtering is complete, the final IQR data set is the final set of “recent sales.”
- Step 3: if the final set of “recent sales” is greater than zero, then the newest sale in “recent sales” is the “representative sale.”
- Step 4: if the set of “recent sales” is zero, then the newest sale is the “representative sale.”

4. Apply Index

If the "representative sale" occurred within the last 2 weeks, then no index adjustment is applied.
If the "representative sale" occurred more than 2 weeks ago, then an index is identified and applied, subject to the two following constraints:
- The index must have a data point within 60 days of the "representative sale," or else no CLV is calculated.
- The index must have a data point within 60 days of today, or else no CLV is calculated.
If those conditions are satisfied, then the index is applied as follows:
- The "representative sale" price is divided by the value of the index on the date of the "representative sale." This produces a ratio.
- That ratio is applied to the index’s current value. This produces the CLV.

5. Index Used

Step 1: check for player/character index.
Step 2: if there is no matching player/character index, then check for category index: Pokemon, Magic, Marvel, One Piece, Star Wars, Yugioh.
Step 3: if there is no matching category index, then default to the CL50 index.

Illustration

Let's now demonstrate this process with an example.

Identification

The exact graded card is:
- card: 1998 Stadium Club #195 Peyton Manning
- grade: 10
- grading company: PSA

Choose the “Representative Sale”

Step 1: Identify recent sales.
- Gather all sales within the last 6 months.
  - Assume July 6, 2026 is today. Accordingly, the last 6 months runs back to January 6, 2026.
  - There are 26 sales in the last 6 months.
  - Because there are more than 10 sales in the last 6 months, we narrow the "recent sales" to the last 3 months.
- Using July 6, 2026 as today, the last 3 months runs back to approximately April 6, 2026.
  - There are 11 sales in the last 3 months:
    - Jul 5, 2026... $125.00
    - Jul 4, 2026... $154.25
    - Jul 1, 2026... $125.00
    - Jun 27, 2026... $125.00
    - Jun 16, 2026... $244.53
    - Jun 6, 2026... $120.00
    - May 13, 2026... $130.00
    - May 4, 2026... $124.50
    - May 3, 2026... $132.50
    - Apr 20, 2026... $199.98
    - Apr 8, 2026... $120.00
- Because the set of "recent sales" is larger than 3, we apply IQR filtering.
Step 2: Apply IQR filtering
- There are only 11 "recent sales," so all 11 are used in the IQR data set.
- Sorted by price, the IQR data set is:
  1. $120.00
  2. $120.00
  3. $124.50
  4. $125.00
  5. $125.00
  6. $125.00
  7. $130.00
  8. $132.50
  9. $154.25
  10. $199.98
  11. $244.53
Calculate Q1
- Q1 position = (11−1) × 0.25 = 2.5
- That means Q1 sits halfway between the 3rd and 4th values.
  - The 3rd value is $124.50.
  - The 4th value is $125.00.
  - Q1 = $124.75.
Calculate Q3
- Q3 position = (11−1) × 0.75 = 7.5
- That means Q3 sits halfway between the 8th and 9th values.
  - The 8th value is $132.50.
  - The 9th value is $154.25.
  - Q3 = $143.38.
Calculate IQR
- IQR = Q3 − Q1
  - IQR = $143.38 − $124.75 = $
Apply the Tukey IQR rule
- Multiply the IQR by 1.5:
  - 1.5 × $18.63 = $27.94
- Lower fence:
  - Q1 − (1.5 × IQR)
    - $124.75 − $27.94 = $96.81
- Upper fence:
  - Q3 + (1.5 × IQR)
  - $143.38 + $27.94 = $171.31
- Therefore, remove any sale below $96.81 or above $171.31.
  - Sales removed by IQR—
    - Two sales are above the upper fence and therefore removed:
      - Jun 16, 2026... $244.53
      - Apr 20, 2026... $199.98
    - No sales are below the lower fence.
Final set of "recent sales" (9) after IQR filtering:
- Jul 5, 2026... $125.00
- Jul 4, 2026... $154.25
- Jul 1, 2026... $125.00
- Jun 27, 2026... $125.00
- Jun 6, 2026... $120.00
- May 13, 2026... $130.00
- May 4, 2026... $124.50
- May 3, 2026... $132.50
- Apr 8, 2026... $120.00
Step 3: Select the "representative sale"
- Because the final set of "recent sales" is greater than zero, the newest sale in the final recent-sales set becomes the "representative sale."
  - The newest remaining sale—and, thus, the "representative sale"—is:
    - Jul 5, 2026... $125.00

Apply Index?

The "representative sale" occurred on July 5, 2026.
Today is July 6, 2026.
So the "representative sale" occurred within the last 2 weeks.
Under the rule set: If the "representative sale" occurred within the last 2 weeks, then no index adjustment is applied.
Therefore, no Peyton Manning index, category index, or CL50 index adjustment is needed.

CLV Result

Because the "representative sale" occurred within the last 2 weeks, the CLV equals the "representative sale" price.
Thus, the CLV is $125.00.

Modified Example to Include Index Application

Now, for the purpose of demonstrating how index application works, assume that the "representative sale" happened before the last 2 weeks.
- We will designate the $120 sale on June 6, 2026 as the "representative sale" and remove all sales after it from the set of recent sales.
- So, the representative sale is: June 6, 2026 ($120) and today is July 6, 2026. Thus, because the representative sale occurred more than 2 weeks ago, an index adjustment is applied.

Index Eligibility

Before applying the index, Card Ladder checks whether the index has sufficient data.
- Constraint 1: the index must have a data point within 60 days of the representative sale. The Peyton Manning index satisfies this requirement.
- Constraint 2: the index must have a data point within 60 days of today. The Peyton Manning index satisfies this requirement as well.
Therefore, the index can be applied.

Index Used

Card Ladder first checks for a matching player/character index.
Because this is a Peyton Manning card, and because there is a Peyton Manning player index, that index is used.
There is no need to use a category index or the CL50 index.

Applying the Index

The representative sale price is: $120.00
The Peyton Manning index value on the representative sale date, June 6, 2026, is 10,325.
Today's Peyton Manning index value (July 6, 2026) is 10,256.
The index is applied as follows.
- First, divide the representative sale price by the index value on the representative sale date:
  - 120 ÷ 10,325 = 0.011622
  - This produces the ratio.
- Then apply that ratio to the current index value:
  - 0.011622 × 10,256 = $119.20
Thus, the CLV is: $119.20.

Identification

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