Yasmin Smith learned the hard way that, when it comes to sustainability and positive impact, not all projects are made equal.

Smith, a university student from Switzerland, signed up through a large, well-known volunteer-placement organization, to spend 10 weeks at an English-teaching program in Madagascar. She hoped that the trip would be long enough to allow her to build connections with her students. She took a TEFL course to prepare for the trip and was looking forward to contributing to the project.

Arriving in Madagascar, she discovered the program was not as advertised. Though the organization had said that volunteers would spend about eight hours a day teaching, there were so many volunteers that each person only taught an hour a day, with the rest of the day off.

“I felt like they just accepted as many volunteers as were willing to come, despite not actually having enough work for all of us,” says Smith. “If people are paying to come, the volunteer organization is not going to say ‘no’ to more volunteers.”

According to Save the Children, the volunteer industry is worth an estimated $2.6 billion a year. With so many volunteer placement organizations out there, how exactly do you determine whether an organization is reputable, that the programs truly empower communities, and that eager volunteers wishing to make a positive contribution aren't being taken advantage of? Here are eight signs to look for.

1. It will connect you with past participants.

This may seem like a no-brainer, but never underestimate the power of word-of-mouth.

Emily Curran, a recent university graduate from Canada, was looking at post-grad plans when she was offered a six-month internship in Spain. The program included work at a local elementary school, a monthly stipend, and Spanish classes. Curran was excited to go—until they asked her send a copy of her passport for “visa purposes,” but dodged questions about specifically what type of visa she would have to apply for.

All of her further questions were met with vague replies and she started to do more research. The organization’s website was filled with positive written and video reviews from people worldwide, but when she searched on other volunteer review sites, she couldn’t find anything. Finally, in an online volunteering forum, she found several other people who had been offered internships with the organization and learned it was a scam designed to steal information such as copies of passports, birth certificates and personal details from hopeful would-be interns.

The lesson here? When reading reviews, be wary of the source—it could very well be the volunteer organization themselves writing those reviews. While reviews can be starting point in determining the legitimacy of an organization, it’s best to ask if you can connect with a past volunteer to hear directly about their experiences.

2. It’s transparent.

The best volunteer organizations will be completely straight-up about where your money is going. Yvette Macabaug, the manager of international volunteering at Cuso International, recommends that potential volunteers ask exactly what their money will be used for. Macabaug also suggests asking organizations: “What is your charitable status?” “How is your organization funded?” And “Where can I access your annual report?”

If an organization is vague, unclear or unwilling to disclose any of this information, move on.

3. It addresses your concerns.

Just because a volunteer organization operates in a particular country doesn’t mean it’s a safe place to travel. Macbaug suggests asking how long the organization has been sending volunteers to the country, how the organization ensures the safety and security of volunteers, and what type of support the organization provides within the country. Look for organizations that address safety concerns honestly and specifically.

4. Education of volunteers is a priority.

Amy Kipp is a research associate at the University of Waterloo who studies the complexity of North-South relationships in the context of international work and travel. Her Master’s research studied volunteer tourism and she stresses the importance of volunteers “learning about the context of the project, as well as the specific issue.” For example, volunteers shouldn’t simply go to help build houses in Central America—they should learn about the socio-economic problems behind why so many people can’t afford basic housing in that region.

Kipp recommends volunteers reflect critically on why they are choosing a volunteer trip. Volunteering abroad can be problematic, as the volunteers’ desire to care for people in less developed areas, particularly those belonging to the Global South, may reflect a long-standing legacy of colonialism.

“People from the Global North may be problematically seen as people with the power to help those they see as “less fortunate” in the Global South,” says Kipp.

Kipp recommends looking for programs that provide resources and require volunteers to learn about the country’s history, geopolitics, and culture ahead of time. Education is the most important aspect of volunteer trips. When you learn about these issues it will help diminish stereotypes and start to change these unequal power relations. It will also make you a more informed global citizen who can share this knowledge and help educate others about these issues.

5. It’s local.

The communities where these programs operate should have the lead in directing how programs run and what they want to get from it. “First and foremost, volunteers should look for programs that are led by or in partnership with local communities,” Kipp says. Look for programs that focus on putting the power back into the hands of the community, not swooping in to help according to an outsider's agenda.

6. It challenges your assumptions.

Communities become aware that volunteers are seeking them out because they are impoverished, and they may get stuck in a “development freeze”— if they progress and appear slightly better off, they risk losing the volunteers and benefits of the volunteer projects. Examples of this include everything from the proliferation of orphanage tourism to people in communities advertised as “authentic” hiding their cell phones and modern amenities while volunteer tourists are present. In both cases, the presence of volunteers prevents the communities from fully developing and commodifies the local people.

Look for a project that challenges your preconceptions of the impoverished, helpless, underdeveloped country. Kipp encourages volunteers to seek programs that promote “opportunities to learn from community members in a way that goes beyond the commodification of culture and highlights local knowledge, experiences, and expertise.” We travel to learn, and the communities we travel to aren’t helpless at all, but have a wealth of knowledge we can learn from.

7. It’s long-term.

Question the project’s short-term versus long-term impact. Projects are often portrayed as contributing to sustainable development, yet only really address the community’s basic needs.

Focusing only on a community’s basic needs restricts their ambitions and doesn’t help them move forward on a path to greater sustainable development. According to Macabaug, long-term assignments of six months or more are key to ensuring impactful work by volunteers, local partners and recruiting organizations. Shorter-term projects can definitely also be helpful, but Macabaug recommends “volunteers ask for a clear role description that outlines how it supports and connects to the bigger project.”

Nothing that lasts is built in a day. If you want to make a contribution that reverberates beyond the time you spend in a place, look for a project that has clearly outlined its goals, both short- and long-term.

8. They truly need volunteers.

There are a lot of people who want to go save elephants in Cambodia, and not so many who want to help out with dungbeetle conservation efforts in Ghana. Once again, consider your motivations behind volunteering: do you want to help where you are most needed, or do you want to help out while travelling?

If you really want to travel and volunteer, look for placements where you have skills that they need and, even better, look for places that aren’t glamorous or trendy. If a project you’re looking at joining has a waiting list or advertises that spots fill up quickly, remember Smith’s story of a program with far more volunteers than they could use. Find out where the help is truly needed, and go there.

Volunteer projects are an amazing way to see the world and be involved in improving it. If you keep in mind these tips on how to pick a reliable, valid, and sustainable project, your work can be rewarding for everyone involved.