The DPA doesn't say how long you should keep personal data, but charities can make a sensible judgment call.
"Our early concept was to go out there getting a lot of data from charities — spreadsheets with outcome data — crunching a lot of numbers," said Alexander Berger, a research analyst at GiveWell.
However, a leading academic and government adviser on health privacy said pursuing a policy that opened up data to charities and companies without clearly spelling out privacy safeguards left serious unanswered questions about patient confidentiality.
Hayhow cautioned that lower numbers counted this weekend would not be enough to give an overall picture of the health of bird populations, but that combined with more than 30 years' worth of data, the charity would be able to look at the longer-term trends and understand how birds are faring.
Neasa MacErlean explains why As the largest UK review of female homelessness is published on Monday, experts urge the Government to tackle the issues affecting this growing and neglected group Financial troubles are making people ill, according to data from charity Christians Against Poverty.
The same agencies provide data as "charity" to humanitarian analysts in order to improve humanitarian response.
It says data showed charity shops "do not increase rents for other shops" and "do not prevent small and medium-sized businesses from opening" on high streets.
After leaving office earlier this year, Bloomberg returned to his self-named firm and also focused his efforts on philanthropy through Bloomberg Philanthropies, a data-driven charity with five areas of focus: public health, arts and culture, the environment, education, and government innovation.
Smile Train, a charity that admits to sharing Barbara's data with other charities explains to Barbara why they traded her name and address - a practice they have since stopped.
To do this research, Yahoo! collected data from 480 charities, collecting the list from the top charities on Forbes and US News, getting top political campaigns, and looking for charities in Wikipedia Current Events.
