2026 GRADED A+ EXAM
Epic Clarity Data Model (CLR) 2025: Exam Prep Set
1. What is the primary purpose of the Clarity Extract process?
• Answer: To move data from the operational Chronometer (M) database to a
relational SQL database.
• Rationale: Epic’s real-time data is stored in hierarchical globals (Chronometer);
Clarity transforms this into a relational format (SQL Server/Oracle) for complex
reporting.
2. Which tool is used to view the metadata, table relationships, and column
descriptions for Clarity?
• Answer: The Clarity Compass.
• Rationale: The Compass is the "dictionary" for Clarity. It provides the mapping
from Chronicles to SQL tables.
3. In Clarity, what does a table name ending in "_2" typically signify?
• Answer: An additional table used to store overflow data from a multiple-
response item.
• Rationale: When an item in Chronicles has too many lines of data for a single
row in the primary table, Clarity uses "overflow" tables (e.g., PATIENT_2 ).
4. What is the difference between a "Load" and an "Extract" in the Clarity
Console?
• Answer: Extract pulls data from Chronicles; Load inserts/updates that data into
the SQL database.
• Rationale: The process is two-fold: pulling the data into flat files (Extract) and
then committing them to the relational tables (Load).
5. Which column in almost every Clarity table acts as the unique identifier for a
specific record?
• Answer: The Primary Key (usually ending in _ID ).
• Rationale: Primary keys maintain referential integrity and allow for joining tables
(e.g., PAT_ID ).
, 2026 GRADED A+ EXAM
6. What is a "Z-table" in the Clarity Data Model?
• Answer: A table that maps internal ID codes to their external, human-readable
names (Categories).
• Rationale: Chronicles stores data as integers (Category IDs); Z-tables
(e.g., ZC_DISP_STU ) provide the string labels (e.g., "Discharged").
7. If a report requires data that is currently in Chronicles but NOT in Clarity, what
must a DBA do?
• Answer: Map a new item in the Clarity Compass and schedule it for extraction.
• Rationale: Clarity is a subset of Chronicles; not all data is moved by default to
save space and processing time.
8. What is the significance of the INTEL column in many Clarity tables?
• Answer: It indicates if the data is "Internal" to Epic and should not be modified.
• Rationale: It helps developers identify system-generated data versus user-
entered data.
9. How does Clarity handle "Multiple Response" items from Chronicles?
• Answer: It creates a separate table where each response is a new row.
• Rationale: Relational databases cannot store multiple values in a single cell, so
a "One-to-Many" sub-table is used.
10. What is the "Clarity Dictionary"?
• Answer: A web-based or Compass-based tool used to search for tables and
columns by keyword.
• Rationale: It is the primary resource for report writers to find where specific
clinical or financial data is stored.
11. What is an "Incremental Extract"?
• Answer: An extract that only pulls data that has changed since the last
successful extract.
• Rationale: This reduces the load on the system by not re-extracting millions of
unchanged records.
12. Which table stores basic demographic information for a patient?
• Answer: PATIENT .
Epic Clarity Data Model (CLR) 2025: Exam Prep Set
1. What is the primary purpose of the Clarity Extract process?
• Answer: To move data from the operational Chronometer (M) database to a
relational SQL database.
• Rationale: Epic’s real-time data is stored in hierarchical globals (Chronometer);
Clarity transforms this into a relational format (SQL Server/Oracle) for complex
reporting.
2. Which tool is used to view the metadata, table relationships, and column
descriptions for Clarity?
• Answer: The Clarity Compass.
• Rationale: The Compass is the "dictionary" for Clarity. It provides the mapping
from Chronicles to SQL tables.
3. In Clarity, what does a table name ending in "_2" typically signify?
• Answer: An additional table used to store overflow data from a multiple-
response item.
• Rationale: When an item in Chronicles has too many lines of data for a single
row in the primary table, Clarity uses "overflow" tables (e.g., PATIENT_2 ).
4. What is the difference between a "Load" and an "Extract" in the Clarity
Console?
• Answer: Extract pulls data from Chronicles; Load inserts/updates that data into
the SQL database.
• Rationale: The process is two-fold: pulling the data into flat files (Extract) and
then committing them to the relational tables (Load).
5. Which column in almost every Clarity table acts as the unique identifier for a
specific record?
• Answer: The Primary Key (usually ending in _ID ).
• Rationale: Primary keys maintain referential integrity and allow for joining tables
(e.g., PAT_ID ).
, 2026 GRADED A+ EXAM
6. What is a "Z-table" in the Clarity Data Model?
• Answer: A table that maps internal ID codes to their external, human-readable
names (Categories).
• Rationale: Chronicles stores data as integers (Category IDs); Z-tables
(e.g., ZC_DISP_STU ) provide the string labels (e.g., "Discharged").
7. If a report requires data that is currently in Chronicles but NOT in Clarity, what
must a DBA do?
• Answer: Map a new item in the Clarity Compass and schedule it for extraction.
• Rationale: Clarity is a subset of Chronicles; not all data is moved by default to
save space and processing time.
8. What is the significance of the INTEL column in many Clarity tables?
• Answer: It indicates if the data is "Internal" to Epic and should not be modified.
• Rationale: It helps developers identify system-generated data versus user-
entered data.
9. How does Clarity handle "Multiple Response" items from Chronicles?
• Answer: It creates a separate table where each response is a new row.
• Rationale: Relational databases cannot store multiple values in a single cell, so
a "One-to-Many" sub-table is used.
10. What is the "Clarity Dictionary"?
• Answer: A web-based or Compass-based tool used to search for tables and
columns by keyword.
• Rationale: It is the primary resource for report writers to find where specific
clinical or financial data is stored.
11. What is an "Incremental Extract"?
• Answer: An extract that only pulls data that has changed since the last
successful extract.
• Rationale: This reduces the load on the system by not re-extracting millions of
unchanged records.
12. Which table stores basic demographic information for a patient?
• Answer: PATIENT .
