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City of Cambridge

Open Data

Open Data

Tips and FAQs

What are the goals of Cambridge’s Open Data Program?

Data created and maintained by the City of Cambridge is a public good and should be released to and leveraged in service of Cambridge’s residents, businesses, and institutions. Cambridge’s Open Data Program is a set of systems, technologies, and policies for maximizing the value of Cambridge’s data while simultaneously maintaining the highest possible degree of protection for privacy and security.

The open data program increases the value of city data by:

  • Releasing data in service of transparency and community engagement, so that residents understand what their city is doing.
  • Enabling city staff and the public to use the data in analyses and software applications that help Cambridge deliver services more efficiently.
  • Providing businesses and other organizations with relevant data at no cost, so that Cambridge continues to maintain a thriving local economy.
  • Removing silos between city departments, thereby fostering data-sharing and enabling efficiency improvements for city service delivery.

How does Cambridge think about protected data?

The open data program protects privacy and security by:

  • Evaluating which datasets should be released at which level of access. 
  • Marshalling technical systems that allow for different tiers of access to the City’s data resources. 
  • Implementing controls such as anonymization and aggregation to prevent the public release of protected data. 
  • Soliciting input from city staff and residents about the proper balance of privacy and transparency.

To learn more about how the open data program thinks about protected data, take a look at our open data ordinance or the materials from our open data review board meetings

Some Cambridge open datasets note that locations have been "geomasked." What does that mean?

Geomasking allows us to protect privacy while still allowing visitors to use open data to create useful maps and analyses. Cambridge's open data program is committed to ensuring privacy and protecting personal information. Yet we also want to provide the public with as much interesting and useful data as possible. Sometimes, we want to release spatial data (which is useful for creating maps), but don't want to reveal precise locations. In these cases, we "geomask" spatial data by adding a little bit of randomness to the latitude and longitude coordinates. The amount of randomness we add depends on several factors, including the area of interest, number of data points, and the sensitivity of the dataset. This creates a new map where each point is moved a little bit away from its original location in a random direction. Open datasets that have been geomasked are labelled as such. We will continue to improve our geomasking and anonymization efforts over time.

Whom should I contact if I notice a potential data privacy issue?

Please send an email to OpenData@CambridgeMA.GOV. We’ll get in touch with you shortly

Last Updated: 5/25/2017

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