Biotechnology for Health (Biomedical Innovations)

Unit 5: Problem 5: Combating a Public Health IssueBI 5.1Biomedical Innovation: epidemiology & public health

Build a line list

Turn scattered case reports into one organized table: a line list: so you can spot who got sick, when, and who they were near.

Builds on (2 levels back)inferred · high confidence

Organizing data into rows and columns: A line list is a table where each row is one case and each column is one fact about that case; you must be able to sort information into a consistent table before you can read patterns from it.
Reading dates and ordering events in time: Onset dates only become useful when you can put them in order; sequencing who got sick first depends on comparing dates.

Prerequisites are inferred: pending teacher review.

Re-learn the skill with worked practice and clear examples.

A line list is one table: each row is a case (a sick person) and each column is one fact, such as onset (when they got sick), symptom, and contact (who they were near).

Step 1: Read the table by row and column

To learn about one person, read across their row. To compare one fact across everyone: like every onset date: read down that column.

Step 2: Use it to spot the first case and shared contacts

Sorting by the onset column shows who got sick first. Scanning the contact column shows who was near the same people or places, which is where contact tracing starts.

Step 3: Watch the trap

Contact tracing means following the people a case was around to see if they are also at risk: it is a next step that the contact column makes possible, not the same thing as the list itself.

Practice

An investigator built this line list. Reading it, who became sick FIRST?

Reviewed

Case	Onset	Symptom	Contact
1	Wed	fever	Cafeteria
2	Mon	cough	Cafeteria
3	Thu	fever	Gym
4	Tue	cough	Cafeteria

A.Case 1
B.Case 2
C.Case 3
D.Case 4

Show the worked solution ▾

Answer: B. Case 2

Step 1: Look down the Onset column: The onset days are Wed, Mon, Thu, Tue. Ignore the row numbers and compare the dates.
Step 2: Find the earliest day: Monday comes before Tuesday, Wednesday, and Thursday, so the Monday case is first.

Why it's right: Case 2 has the earliest onset (Monday), so that person became sick before the others.

Why the others miss:

A: Case 1's onset is Wednesday, which is later than Monday.
C: Case 3's onset is Thursday, the latest day in the table.
D: Case 4's onset is Tuesday, one day after the Monday case.

Aligned to BI 5.1: reading a line list · reading level ~grade 9

Where you'd see this

A health department turns a stack of phone-in reports into a line list, then sorts by onset to find the index (first) case.

Careers that use this

Public Health Nurse: Keeps a running line list during an outbreak and uses the contact column to decide who to call for tracing.

Video library

Watch: Build a line list

How Do We Investigate Outbreaks? Epidemiology: Crash Course Outbreak Science #8

CrashCourse · ~12 min

Guided notes

Fill these in as you work through the lesson.

Big idea: A line list is a single table where each row is one sick person (a case) and each column records one fact about them, so an investigator can see the outbreak at a glance.

Key terms: write the meaning

Line list (one row holds everything about a single person):
Case (the person each row stands for):
Onset (the calendar word: when it started):
Contact tracing (follow the people a case was near):

The rule

In a line list, each of the table is one case, and each of the table is one fact you collected about that case.

Check yourself

An investigator has four messy reports of sick students. What columns would you set up so every report fits the same table?
Why is it easier to find the first person who got sick when the cases are in a line list instead of in four separate notes?
A row says a case ate at the cafeteria and shares a bus with two other cases. Which column would let you start contact tracing?

Work one example

You have three reports: Ana: felt sick Monday, fever, rode Bus 7. Ben: felt sick Tuesday, cough, rode Bus 7. Cyn: felt sick Wednesday, fever, rode Bus 3. Put these into a line list with the columns Case, Onset, Symptom, Bus, and say who got sick first.