COVID-19 case data: Glossary

Definitions of terms used on the COVID-19 case data graphs and tables.

7-day average / 5-day average / Rolling average
Each point on the these charts/tables is the average of the previous 7 or 5 days, as noted. This approach smooths out the data which makes it easier to understand general trends.
The number of people who have tested positive and have not yet been changed to “resolved” or "deaths".
Cases per 100,000
The number of cases for every 100,000 people in the region. It is calculated by dividing the number of cases by the population, and then multiplying by 100,000. For example, if a region has a rate of 24 per 100,000 population, there are 24 cases for every 100,000 people.
The total number of cases or tests since we started counting them. Each day's total is added to the total of all previous days.
The number of people with a confirmed case of covid 19 who died.
Effective reproduction number (Re)
An estimate of the average number of people that 1 person will infect when they have covid 19 .
  • When Re is less than 1, the number of new cases are expected to decrease over time because 1 person will infect fewer than 1 other person.
  • When Re equals 1, the number of new cases will not change because 1 person infects 1 other person.
  • When Re is more than 1, the number of new cases are expected to increase. For example, if Re = 2, 1 person will infect 2 people. Those 2 people will then each infect another 2 people, and so on.
  • When Re is equal to or greater than 1, effective control measures are needed to reduce the spread, otherwise, the average number of new cases will keep growing.
Re can be translated into projections about how quickly the number of daily cases will increase or decrease. For example:
  • When Re equals 1.2, the number of new cases can be projected to increase by 33% in the next 7 days.
  • When Re equals 0.8, the number of new cases is projected to decrease by 29% in the next 7 days.
The total number of people in the hospital because of covid 19, which includes people in an Intensive Care Unit (ICU) and people not in an ICU.
This number includes patients who are in an Intensive Care Unit (ICU) levels 2 and 3 flex, neonatal, pediatric and adult. It includes people who are on ventilators and people who are not.
In ICU with a ventilator
This is the number of people in the ICU who are on a ventilator, which helps them breathe, because they cannot breathe on their own.
Likely source of infection
Close contact
Individuals who likely caught covid 19 from an infected person that they were physically close to.
Community spread
A case is considered “community spread” when someone tests positive but we cannot trace the source because the person:
  • did not travel
  • did not knowingly have contact with another infected person
  • is not associated with an outbreak
Outbreak setting
Individuals who caught covid 19 in a specific shared space or setting such as a workplace, long-term care home or daycare.
Individuals who travelled outside of Ontario within 14 days before their symptoms began.
Information on the source of infection is currently pending or unspecified.
Different facilities have different definitions of “outbreak”. We have explained the criteria for each below.
Care setting (also called congregate care)
Long-term care home or Retirement home
  • 2 or more patients or staff with covid 19 within a specified area (such as a unit or floor)
  • cases happen within 14 days and both people could have reasonably been infected in the hospital (for example, there was not an obvious source outside of the hospital or a patient didn’t have symptoms for at least 5 days after going into the hospital)
Group living (also called congregate living)
  • Group home or supportive housing
  • Correctional facility
  • Shelter
  • Short-term accommodation (such as a hotel, hostel, motel or airbnb)
  • Other group living
Outbreak criteria:
All schools (all levels, public and private)
  • 2 or more students, staff or visitors with covid 19 within 14 days
  • at least 1 of the infected people could have reasonably been infected in the school (for example, there was no obvious source outside the school or exposure at the school was obvious), including transportation to and from school and before- and after-school activities
  • school outbreaks are reported beginning the week of August 30th
  • get more details from covid 19 Guidance: School Outbreak Management (PDF)
Child care
  • 2 or more children, staff/care providers or visitors with covid 19 within 14 days
  • at least 1 of the infected people could have reasonably been infected in the child care setting (for example, they were in the same room or part of the same care group)
  • settings include licensed and unlicensed child care, child drop-in programs (for example, EarlyON), children’s educational or recreational camps, preschool and afterschool programs)
  • before November 9, 2020 an outbreak at a child care setting was considered 1 or more children or staff/care providers with covid 19
  • get more details from Operational Guidance During COVID-19 Outbreak (PDF)
Local medical officers of health declare outbreaks in these settings based on their investigation. Typically, they’ll need to find at least 1 case in a defined setting within a specific timeframe. These are the definitions for each setting.
Bar, restaurant or nightclub
  • a place for socializing or entertainment where you can get food and/or drinks
Recreational fitness
  • a place you exercise, for example: gyms, yoga studios
Personal service setting
Other recreation
  • a place that is not for fitness but for leisure time such as venues for weddings and religious activities
Farm (an area of land and its buildings used for growing crops and/or rearing animals)
Other workplaces:
  • Retail (for example: grocery stores, pharmacies, shopping malls)
  • Medical/health service (for example: doctors’ offices or clinics, wellness clinics, dental offices, at-home care)
  • Food processing (a commercial operation that processes food for humans and sells or distributes it to restaurants and grocery stores)
  • Other workplace (for example: offices, warehouses, shipping and distribution centres, construction sites)
Outbreak criteria:
  • 2 or more cases within 14 days
  • both people could have been reasonably infected in the workplace (for example in the same work area or during the same shift and there was no obvious source outside the workplace or exposure at the workplace was obvious)
  • get details from covid 19 Guidance: Workplace Outbreaks (PDF)
Unknown or other
Unknown outbreak setting
  • we are missing data or do not have enough data to classify the setting
Other outbreak setting
  • any setting that has not been classified in the definitions above
Percent positive
The proportion of lab tests processed that had a positive result. It is calculated by dividing the number of tests with a positive result by the total number of tests processed in a day, and then multiplying by 100.
Cases are classified as “resolved” if they are:
  • reported as “recovered” in Ontario’s Case and Contact Management system (CCM)
  • not hospitalized and are 14 days past the day symptoms began or (if no symptoms) they tested positive
  • currently hospitalized and have a status of “closed” in CCM (indicating Public Health Unit follow-up is complete) and are 14 days past the day symptoms began or (if no symptoms) they tested positive
Cases are not classified as “resolved” if they result in death.
There was a spike in resolved cases on March 30 because the reporting changed. Before March 30, “resolved” was called “recovered” and only included people who tested positive for covid 19 but had since had two negative tests in a row, at least 24 hours apart.
Tests completed
The number of tests that were processed by the lab for covid 19 on a given day (some people are tested more than once, so this is higher than the number of people tested).
Total cases
The number of cases since January 15, 2020. This number includes cases that have been changed to “resolved” or “deaths”.
Total tested
We changed how we report "total tested" on April 15:
  • Current definition (from April 15 on): the total number of tests completed
  • Definition until April 14: the total number of people tested