Wherever we look, there is a demand for data about Covid-19. We devour dashboards, graphs and visualisations. We want to know about the numbers of tests, cases and deaths; how many beds and ventilators are available, how many NHS workers are off sick. When information is missing, we speculate about what the government might be hiding, or fill in the gaps with anecdotes.

Data is a necessary ingredient in day-to-day decision-making – but in this rapidly evolving situation, it’s especially vital. Everything has changed, almost overnight. Demands for food, transport, and energy have been overhauled as more people stop travelling and work from home. Jobs have been lost in some sectors, and workers are desperately needed in others. Historic experience can no longer tell us how our society or economy is working. Past models hold little predictive power in an unprecedented situation. To know what is happening right now, we need up-to-date information.

This data is also crucial for scientists, who can use it to replicate and build upon each other’s work. Yet no open data has been published alongside the evidence for the UK government’s coronavirus response. While a model that informed the US government’s response is freely available as a Google spreadsheet, the Imperial College London model that prompted the current lockdown has still not been published as open-source code. Making data open – publishing it on the web, in spreadsheets, without restrictions on access – is the best way to ensure it can be used by the people who need it most.

There is currently no open data available on UK hospitalisation rates; no regional, age or gender breakdown of daily deaths. The more granular breakdown of registered deaths provided by the Office of National Statistics is only published on a weekly basis, and with a delay. It is hard to tell whether this data does not exist or the NHS has prioritised creating dashboards for government decision makers rather than informing the rest of the country. But the UK is making progress with regard to data: potential Covid-19 cases identified through online and call-centre triage are now being published daily by NHS Digital.

Of course, not all data should be open. Singapore has been publishing detailed data about every infected person, including their age, gender, workplace, where they have visited and whether they had contact with other infected people. This can both harm the people who are documented and incentivise others to lie to authorities, undermining the quality of data.

When people are concerned about how data about them is handled, they demand transparency. To retain our trust, governments need to be open about how data is collected and used, how it’s being shared, with whom, and for what purpose. Openness about the use of personal data to help tackle the Covid-19 crisis will become more pressing as governments seek to develop contact tracing apps and immunity passports.

And it is not only governments that have a role to play. Private-sector organisations already hold data that can help inform both public policy and our daily choices. Citymapper, for example, is publishing information about the use of their app in cities around the world, demonstrating the effectiveness of lockdown orders, and complementing similar aggregated data about population movements from mobile-phone companies.

On the basic Covid-19 figures, some best practices are developing across the world. Italy has been publishing open data daily on GitHub since the beginning of March, with regional breakdowns, and numbers of people self-isolating, hospitalised and in intensive care. Belgium is providing province-level open data on cases and deaths, broken down by gender and age group, and numbers of people in hospital, ICU, and receiving respiratory support.

To coordinate our response to Covid-19, we need a common bid to equip everyone with the data they need. That requires an ongoing effort from governments, scientists, charities and companies to make any data they hold that could inform our response to Covid-19 as open as possible.

• Jeni Tennison is vice-president of the Open Data Institute.

• The subheading of this article was amended on 6 April 2020 to make clear that it is open data which is the subject of the article. An earlier version had referred to “open-source information”, which is not the same thing and relates to computer programming code or software.