In the days since the arrival of Hurricane Harvey, which has brought intense flooding and displaced tens of thousands in Houston and the surrounding areas, people across the globe have rushed to assist those affected by the natural disaster.

There have been GoFundMe pages, food and supply drives, and some — including former Red Sox pitcher Curt Schilling — who have decided to simply pack up a truck and head south to Texas.

For those hoping to have the most significant effect, however, it’s worth noting that some methods of giving can be far more effective than others.

And the best way, according to the organizations that routinely provide aid in such cases, is often the easiest: a monetary contribution.

“Not to be cute, but money’s the currency we can trade in,’’ says Mike Durkin, president of United Way of Massachusetts Bay and Merrimack Valley. “People want to donate materials and so forth, and that’s good, but money gives the organizations that are going to help the greatest flexibility to respond to the needs.’’

Some groups, for instance, have partnerships with businesses that allow them to purchase bulk items at a much cheaper rate than the general public, making the money stretch further. It also allows them to focus on acquiring the kinds of goods that will be most needed by victims going forward — medicine, for instance — rather than being inundated with piles of goods that might not be in demand.

“A warehouse full of snack food isn’t necessarily the thing we’re going to need to get people the nutrition they’re going to need,’’ says Lynn Levine, director of communications for the Massachusetts region of the American Red Cross. “It needs to be thoughtful and coordinated.’’

Michael J. Nyenhuis, the president and chief executive of Connecticut-based relief and development organization Americares, knows that it sounds self-serving to ask for money rather than donated goods. And the last thing he wants to do, he says, is diminish the compassion of people wanting to help in a time of need.

But having aided in disasters across the world, he says, Americares is professionally qualified to provide the goods and services victims most need — and it requires money, not donated goods, to most effectively do that.

“The reality is a lot of the goods that are sent by well-meaning people who don’t have a real experience in responding in a disaster like this, a lot of those goods are wasted,’’ he says. “The wrong things [come] at the wrong time; they don't get to the right people.’’

In fact, bundling up bags of food, clothing, and bedding to donate can not only be ineffective — it can often be detrimental.

“As far as the Red Cross — and I think if you call other relief organizations you’ll get a similar response — material donations can often impede our relief efforts by clogging up a supply chain, by incurring costs for shipping, warehousing, transportation, storage,’’ Levine said. “And then it also requires personnel to sort and distribute.’’

Nevertheless, there’s skepticism in some quarters about the manner in which monetary donations are spent by relief organizations. And that spending has occasionally come under scrutiny.

In a scathing 2015 investigation, for example, ProPublica and NPR reported that after raising nearly half a billion dollars in the wake of the earthquake in Haiti, the American Red Cross had built just six permanent houses there. Years later, the echoes of that investigation continue. On social media, some are requesting that donations be made to small, grass-roots organizations to help the people of Texas.

Meanwhile, dozens of people are volunteering to go to Texas to help on the ground.

To date, 42 volunteers from Massachusetts have been sent to Houston through the Red Cross, and the organization will host three training courses in Cambridge between Thursday and Monday for volunteers hoping to “fast-track’’ into the group’s Harvey response effort.

Here in Boston, meanwhile, some city employees have begun volunteering during their lunch-breaks to help sort and label the boxes of goods that have been pouring into City Hall and nearly 40 other city drop-off spots.

For those contemplating a trip to Houston to help, meanwhile, Nyenhuis suggests first coordinating with a group on the ground that is seeking volunteers.

“With the Internet today, you can probably find an institution, a local nonprofit, or a faith community or a government agency’’ that's asking for people, he says. “Otherwise, you take the risk of frustrating yourself because you drive all the way down there and can’t figure out what to do.’’

As the storm moves toward its second week, meanwhile, relief organizations urged would-be donors to remember that the effects of the flooding are going to be felt in Texas for years to come.

In other words, much like hurricanes Sandy and Katrina, help will be needed long after the cameras and politicians have packed up and left the state.

“This is a long-haul kind of response,’’ says Durkin, of United Way. “The thing I would say to folks is let’s all pitch in as much as we can to stabilize the current situation, but also keep an eye on the long-term rebuilding needs that Houston is going to experience.’’

Dugan Arnett can be reached at dugan.arnett@globe.com. Follow him on Twitter @duganarnett.