Line list

H1: original records and the full task

This is a new, entirely invented Cedar cohort. No person was observed. Its thirty case reports are not official PLTW data or individual records reconstructed from Alder’s aggregate numbers.

Warmup: name the fields you would record for a hypothetical new COVID case. Use a case ID, onset date, symptoms and outcome; do not provide names or personal illness details.

Answer both starting questions: how would you organize thirty sticky-note case reports, and how does sick-now differ from new-this-week? Keep your first answer for revision.

The full product is a thirty-row line list with four required columns, incidence and prevalence calculations, and a written trend observation. Include the onset graph required for this week.

Work independently from the supplied reports. Actual assigned spreadsheets, official case files, prior debate participation and live submissions remain separate when absent.

E1: case records and frequency rules

CDC explains that a common case definition makes counting consistent. A line list uses one row per case and the same fields in every row.

Onset is when the defined illness begins. Report date is when information is received; exposure date is a different event. Do not substitute one for another.

New-case count means onsets inside a defined window. Current-case count means cases still active at the stated instant. Both counts need the population and time to be interpretable.

Incidence proportion equals new cases divided by the initially disease-free people at risk for that window. Point prevalence equals current cases divided by the population at that instant.

Multiply a proportion by 100 for a percentage. Incidence rate uses person-time at risk; that denominator is not supplied, so this lesson does not calculate a person-time rate.

A cases-only list does not supply the full population denominator. Use D1’s separate population rules. A five-case practice subset is not a complete population record.

Frequency alone does not measure severity or transmission speed. A change in observed onsets can be described without claiming why it happened.

D1: Cedar population, dates and case rules

Cedar is a fictional residential learning program with 300 adults. Membership is fixed from the start of April 1 through the end of April 14, 2027.

At the start of April 1, all 300 are disease-free and at risk. No births, deaths or moves occur. All thirty reports are unique valid cases from this cohort.

A case first develops both fever and cough. Its onset date is when both required symptoms first coexist. Additional sore throat does not change eligibility.

Recovery is when both required symptoms have ended. Recovery on a date counts as recovered by that date’s end. This is a fictional counting rule, not a medical diagnosis.

Each adult can contribute only one first episode. Earlier cases stay excluded from a later at-risk denominator even after recovery; repeat episodes are outside this exercise.

The first window is April 1–7, inclusive. Its initial at-risk denominator is 300. The second window is April 8–14, inclusive; its denominator is 300 minus the first cases counted in April 1–7.

Case finding is complete every day, with the same criteria and no missed cases, duplicate reports or delays stipulated. All outcomes in D2 are known at the end of April 14.

The expected background is stipulated as zero to one new case per seven days in this population under the same method. It is a teaching assumption, not a measured prior series.

No exposure dates, infection-acquisition times, organism, transmission links, severity or treatment effects are supplied. Symptom onset does not locate an exposure or prove a source.

Use the unambiguous YYYY-MM-DD date format. Preserve an active outcome as active at the cutoff; do not invent a future recovery date.

D2: all thirty unsorted original reports

Report K18: both required symptoms first coexisted on 2027-04-10. Recorded symptoms are fever and cough; sore throat. Both required symptoms ended on 2027-04-13.

Report K02: both required symptoms first coexisted on 2027-04-03. Recorded symptoms are fever and cough. Both required symptoms ended on 2027-04-06.

Report K25: both required symptoms first coexisted on 2027-04-12. Recorded symptoms are fever and cough. The required symptoms remain active at the end of 2027-04-14.

Report K08: both required symptoms first coexisted on 2027-04-05. Recorded symptoms are fever and cough. Both required symptoms ended on 2027-04-08.

Report K01: both required symptoms first coexisted on 2027-04-02. Recorded symptoms are fever and cough. Both required symptoms ended on 2027-04-05.

Report K14: both required symptoms first coexisted on 2027-04-09. Recorded symptoms are fever and cough. Both required symptoms ended on 2027-04-12.

Report K22: both required symptoms first coexisted on 2027-04-11. Recorded symptoms are fever and cough. The required symptoms remain active at the end of 2027-04-14.

Report K05: both required symptoms first coexisted on 2027-04-04. Recorded symptoms are fever and cough. Both required symptoms ended on 2027-04-07.

Report K29: both required symptoms first coexisted on 2027-04-13. Recorded symptoms are fever and cough. The required symptoms remain active at the end of 2027-04-14.

Report K11: both required symptoms first coexisted on 2027-04-06. Recorded symptoms are fever and cough. Both required symptoms ended on 2027-04-09.

Report K04: both required symptoms first coexisted on 2027-04-04. Recorded symptoms are fever and cough. Both required symptoms ended on 2027-04-07.

Report K17: both required symptoms first coexisted on 2027-04-10. Recorded symptoms are fever and cough. Both required symptoms ended on 2027-04-13.

Report K27: both required symptoms first coexisted on 2027-04-12. Recorded symptoms are fever and cough; sore throat. The required symptoms remain active at the end of 2027-04-14.

Report K07: both required symptoms first coexisted on 2027-04-05. Recorded symptoms are fever and cough. Both required symptoms ended on 2027-04-08.

Report K20: both required symptoms first coexisted on 2027-04-11. Recorded symptoms are fever and cough. The required symptoms remain active at the end of 2027-04-14.

Report K10: both required symptoms first coexisted on 2027-04-06. Recorded symptoms are fever and cough. Both required symptoms ended on 2027-04-09.

Report K30: both required symptoms first coexisted on 2027-04-14. Recorded symptoms are fever and cough; sore throat. The required symptoms remain active at the end of 2027-04-14.

Report K03: both required symptoms first coexisted on 2027-04-03. Recorded symptoms are fever and cough; sore throat. Both required symptoms ended on 2027-04-06.

Report K23: both required symptoms first coexisted on 2027-04-11. Recorded symptoms are fever and cough. The required symptoms remain active at the end of 2027-04-14.

Report K13: both required symptoms first coexisted on 2027-04-08. Recorded symptoms are fever and cough. Both required symptoms ended on 2027-04-11.

Report K06: both required symptoms first coexisted on 2027-04-04. Recorded symptoms are fever and cough; sore throat. Both required symptoms ended on 2027-04-07.

Report K26: both required symptoms first coexisted on 2027-04-12. Recorded symptoms are fever and cough. The required symptoms remain active at the end of 2027-04-14.

Report K16: both required symptoms first coexisted on 2027-04-10. Recorded symptoms are fever and cough. Both required symptoms ended on 2027-04-13.

Report K09: both required symptoms first coexisted on 2027-04-06. Recorded symptoms are fever and cough; sore throat. Both required symptoms ended on 2027-04-09.

Report K24: both required symptoms first coexisted on 2027-04-11. Recorded symptoms are fever and cough; sore throat. The required symptoms remain active at the end of 2027-04-14.

Report K12: both required symptoms first coexisted on 2027-04-07. Recorded symptoms are fever and cough; sore throat. Both required symptoms ended on 2027-04-10.

Report K28: both required symptoms first coexisted on 2027-04-13. Recorded symptoms are fever and cough. The required symptoms remain active at the end of 2027-04-14.

Report K15: both required symptoms first coexisted on 2027-04-09. Recorded symptoms are fever and cough; sore throat. Both required symptoms ended on 2027-04-12.

Report K21: both required symptoms first coexisted on 2027-04-11. Recorded symptoms are fever and cough; sore throat. The required symptoms remain active at the end of 2027-04-14.

Report K19: both required symptoms first coexisted on 2027-04-10. Recorded symptoms are fever and cough. The required symptoms remain active at the end of 2027-04-14.

R1: build and check the full line list

Create four columns: case ID; onset date; symptoms; outcome at the end of 2027-04-14. In outcome, preserve the supplied recovery date or write active at cutoff.

Begin with one supplied report as your starter row, not a personal case. Then enter all thirty reports once. Keep each ID attached to its own dates and symptoms.

Check completeness by locating K01 through K30. Compare every row with D2, then sort a copy by onset date. Sorting changes row order, not any case value.

If behind, first enter K01, K02, K03, K04 and K05. Count their onsets within April 1–7 as a five-report exercise, then return to the other twenty-five.

That small set contains five first-window onsets. It does not give the full cohort’s new-case count or population incidence; finish the complete file before calculating those.

Count each full window’s onsets using inclusive dates. Count active cases at the final cutoff using outcomes, not the total number of historical rows.

Show the numerator, denominator, fraction and percentage for both windows and final point prevalence. State why the second window’s at-risk group is smaller.

Restart by checking the four columns, case IDs and cutoff. Then finish the rows, calculate full counts and proportions, and return to the graph and observation.

G1: the original onset graph task

Tally onsets for every date from April 1 through April 14. Include dates with zero cases. The fourteen equal-width daily bins must sum to all thirty reports.

Build an onset-count graph with calendar date on x and number of new onsets on y. Use equal daily widths, whole-number count ticks and a zero baseline.

Use adjacent bars for the daily time bins. Title the graph Original Cedar onset counts, April 1–14, 2027. Label it invented instructional data and state the end-of-April-14 cutoff.

Use each case’s onset date, not its recovery date. A report remaining active does not become a new case on every later day.

Write one observation comparing the two complete seven-day windows, with their actual counts or proportions. Also describe the largest observed daily bin and the later observed bins.

The highest observed bin is not proof of a final outbreak peak. The graph stops at its cutoff; no subsequent onsets are known. Do not claim that a control measure caused a change.

Optional extension: predict next week’s new-case count conditionally. Name an assumption and explain why the observed data cannot guarantee your prediction; do not enter it as an observed bar.

The linked Cedar practice workbook uses the same reports with blank line-list and graph areas. It is original practice, not the teacher-provided official dataset.

Q1: checks with counts kept separate from proportions

Cedar check: count each window’s new onsets first. Divide the first count by 300 and the second by 300 minus the first count, then convert each fraction to a percentage.

At the final cutoff, count only cases still active; recovered cases leave the prevalence numerator. Point prevalence is active cases over 300, not 30/300. Thirty is the cumulative number of case rows.

Whichever complete week has more new onsets, that statement does not establish transmission speed, severity or cause. The daily pattern may differ from the weekly comparison.

Separate self-check: imagine a different fixed population of 500 adults and fifty unique valid case rows by the end of one week. Thirty-six cases were active at the start.

The other 464 adults were initially disease-free and at risk. Fourteen new first cases occur during the week. Eight of the initial cases recover by the cutoff.

All other cases remain active; no new case recovers. No death, move, repeat episode, future onset, missing outcome or duplicate occurs. This is not the Cedar dataset.

Find the new and current counts, then both proportions. The counts are fourteen new and 50 − 8 = 42 current. Incidence proportion is 14/464, about 3.02%.

Point prevalence is 42/500 = 8.4%. Without the stated outcome and membership assumptions, fifty rows minus eight recoveries alone would not establish the active count.

If your prevalence used every row, reread outcomes. If you called fourteen a rate, state the count first and then supply the correct denominator for the proportion.

P1: actual course, spreadsheet and submission status

Open Project 5.1.1 Disease Detectives and build the line list. The project has versions A and B with separate conclusions; ask your teacher which version you are assigned.

Keep the assigned Disease Detectives diagnostic evidence, epidemiological studies and prevention/control planning separate from this original line-list exercise. Ask your teacher which sections to complete.

Actual evidence reports, study-design materials, later sections, version B, mission files and conclusion questions remain needed. No official case data or assigned stopping point is supplied here.

The absence branch requires the provided spreadsheet outbreak dataset, its assigned window, a line list and both calculations. An original Cedar spreadsheet is a separate practice resource.

Use the complete paper inputs or the linked original Cedar practice workbook. Keep the teacher-assigned spreadsheet task pending until you have its dataset and complete the assigned work. A PDF does not replace that spreadsheet.

After completing the assigned work, save the required line-list screenshot for your Problem 5 evidence portfolio. Mark the upload pending until you have actually uploaded it.

Keep the April 19 debate and any unfinished April 16 Project 4.1.4 work on your checklist. Reading a prior lesson or its take-home does not complete that work.

For April 19–23, keep the Wednesday onset graph, Thursday intervention model, line-list lab, assigned spreadsheet and Friday Public health intervention plan on your checklist.

Problem 5 intervention evidence should be complete by Friday. Your original Cedar table and graph do not complete the missing actual model, plan or official evidence.

April 22 requires 25 minutes of Intervention model preparation in Lab Notebooks and plan submission in Lab Reports. Keep that preparation separate from today’s eighty-minute work. No homework is due before this class.

Follow the assignment for April 21, and ask your teacher if you are unsure which tasks and deadlines apply. Keep any confirmed unfinished work on your checklist.

The April 21 assignment lists Data Tables; confirm the folder in your enrolled section before submitting. A course description is not proof of submission.

Save the dated original line list, calculations, graph and observation together as one PDF. Use the linked dated BI assignment and confirm access in your enrolled course section.

Without a confirmed assignment or access, preserve the saved record and mark submission pending. Keep real identities and health details in the teacher-approved private route; record only missing-input status here.

Set up the case record

Answer H1’s starting questions. Use one D2 report as the fictional starter; create the four R1 columns and record the D1 population, windows and cutoff.

No personal case is needed. A source report is input, not a claim that you measured anyone.

Enter all thirty cases

Build the full line list from D2. Check every ID, onset, symptom and outcome against its source; preserve recovery dates and active-at-cutoff status.

Use K01–K05 for recovery, then finish the other twenty-five. Do not submit only the starter subset.

Calculate counts and proportions

Show both full-window new-case counts and incidence proportions, plus final active count and point prevalence. Label every numerator, denominator, time and percentage.

The second at-risk group excludes earlier first cases. Historical case rows are not all still active.

Build the original onset graph

Tally all fourteen dates and draw G1’s graph, including zero bins. Compare weekly counts and describe the largest observed daily bin and later bins.

Use onset, not reporting or recovery. Do not call the graph a transmission-speed or intervention-effect estimate.

Complete the separate self-check

Solve Q1’s separate fifty-case problem with all stated assumptions. Explain why its counts require denominators to become proportions.

Keep Q1’s 500-person population separate from Cedar. Use the optional prediction only after the full record is complete.

Preserve the complete product

Write the trend observation and exit quantities. Check all thirty rows, both windows, prevalence, graph and source labels; record actual spreadsheet, official evidence and submission status.

P1 keeps the editable original-practice workspace separate from the missing teacher-provided dataset and actual course work.