Describing Data



Public Data vs. Private Data

The difference between public and private data may seem obvious at first glance, but it’s important to be clear on what this really means. 

You may have encountered the difference between public and private in other contexts before:

  • Public vs. Private Companies - A public company sells its shares to the public through the stock exchange, while a private company typically has a smaller number of owners and its shares are not sold on the public stock exchange. 

  • Public vs. Private Sector - The public sector is composed of organizations that are owned and managed by the government. In contrast, the private sector is the part of the economy owned and managed by individuals or companies.

As we can see in these examples, public is often linked to things that are more widely held, or widely available, while private is usually associated with things that are more closed and limited. 


Now back to data!

In terms of data, it is well understood that you don’t go around telling people the password to your email address. And you would never post your social insurance number on social media. These data are considered private - it is easy to recognize that we wouldn’t want this information to be widely known. 

Private data refers to any data that is restricted to a specific person or organization. As a result private data is not known to the general public and is not shared without specific agreements in place that control how the data is handled. This can include personal, financial, or other sensitive information that you want to keep private. 

Some specific examples of private data include:
  • House Home address
  • Medical Symbol Medical records
  • Credit Card Financial records (ex: credit card information)
  • Briefcase Business records (ex: clients, internal strategy, budgets)


Public data refers to any information that is made available to the public. It can be freely used and redistributed without any limitations.

Some examples of public data include:
  • Syringe Global health data published by the World Health Organization (WHO), such as the  Global Health Observatory .
  • Chart Increasing  Google Finance  data for public stock markets.
  • Farmer  Farm Income Forecast results  from Agriculture and Agri-Food Canada (AAFC).

Public data can sometimes be confused with open data, but they aren’t exactly the same. Open data is a type of public data that is better maintained and published under a specific open license that specifies how it can be used and redistributed. Public data is not always open data.

If you look at the examples above, these are all instances of public data because there is no visible license that restricts how the information is used. The information is all publicly available and can be freely used.

Module 9 is focused exclusively on open data. We will add a link to that module here when it is published.


Personal Data

Now that you have a better sense of the difference between public and private data, we can look at another important classification: personal data.

Personal data is an important type of information because our federal and provincial privacy laws give it special treatment and protections. For example, the Personal Information Protection and Electronic Documents Act (PIPEDA) is Canadian federal privacy legislation for private-sector organizations.
PIPEDA defines ‘personal information’ as “any factual or subjective information, recorded or not, about an identifiable individual." (Source:   Privacy Commissioner of Canada )

Some examples of this include:
  • Name
  • Age
  • Income
  • Ethnic origin
  • Blood type and other medical records
  • Identification numbers
  • Credit and loan records

Personally identifiable information (PII) is another term that is important here because it represents any data related to an individual that can be used to identify them.  While not all personal data is PII, all PII is personal data . Data anonymization is the process by which PII is removed or modified to produce anonymized data that is more difficult to link back to an individual person. 

There is a dedicated module focused on privacy planned for later in this program which will offer a deep dive into the issues related to privacy. We will add a link to that module here when it is published later in 2024.



Next:  🗄️⁠⁠Organizing Data⁠