With face-to-face meetings discouraged due to COVID-19, at least for now, many of us have switched to using online tools for all sorts of communication. Health care is no exception, with governments, doctors, and patients turning to phones and computers to communicate medical messages. These developments raise a question: how effective can online tools be for delivering health care?

Many aspects of telemedicine are still too new to have been rigorously studied. But the use of text messages to encourage healthy behaviors have been evaluated and found to be effective at shifting people's choices.

The research on the topic has included a wide range of healthy behaviors: getting immunizations, attending medical appointments, taking medications for chronic illnesses like AIDS, quitting smoking, exercising, practicing safe sex, and drinking less alcohol. The text messages did not make a huge difference — but they did nonetheless lead people to make measurably better choices than without text-message reminders.

This evidence comes from a systematic review which combines the results from numerous studies around the world. This approach provides stronger evidence than relying on a single case, where idiosyncratic issues can affect program outcomes. This review included research from 38 studies. The majority were from Europe and the United States, but others were conducted in Brazil, China, India, Kenya, Malaysia, Singapore, and South Africa.

Since the beginning of the COVID-19 pandemic, health text messages have been used in many places for a range of purposes. SMS messages with basic COVID-19 information have been sent in contexts as different as Kenya  and Colorado. The World Health Organization is working with telecommunications companies to keep people informed. And some places, like Israel, are using SMS messages to inform people who may have been exposed to the virus.

Among the earlier studies of SMS health messages in the systematic review, one aspect of the interventions that made a difference in their effectiveness was the number and frequency of text messages. When people got more frequent messages, their behavior changed more. The most effective interventions were those that sent multiple text messages per day.

On the other hand, despite the widely varying types of behaviors included in the review, the effect size was similar for each of them. This finding suggests that regardless of the complexity of a health issue, text-message reminders are likely to lead to a similar, small improvement in people's choices.

It also did not appear to matter whether the text messages were personalized, or if people were able to respond and have a two-way communication with medical professionals.

Other systematic reviews have looked at more specific aspects of health-focused text messaging, and several with medium- or high-quality reviews can be found on our Development Evidence Portal. This review shows text messages improve disease surveillance, disease management, and patience compliance with treatment regimens in developing countries. While another review shows that text messages promote adherence to antiretroviral therapy among HIV patients. This review shows that text messages to new mothers improve some child health outcomes. And this review shows that text messages make people with chronic diseases in developing countries more likely to attend medical appointments.

The full study discussed in this post, as well as 3ie's quality assessment, is here. And there are hundreds more systematic review and thousands more impact evaluations in our Development Evidence Portal.

This blog is part of our campaign 2020 Hindsight: What works in Development. Learn more about the campaign and read past blogs here.