Most philanthropists working with Fidelity Charitable, a donor advised fund, know which charities they want to support, but few have a written plan setting their goals, says a study by Fidelity Charitable released Monday.

Having a defined goal can benefit both the donors and the charities, says Amy Danforth, president of Fidelity Charitable.

“Many of our donors plan to expand their commitment to philanthropy within the next five years, with full-time employed donors in their 50s most likely to anticipate increasing the time they spend on philanthropic activities,” says Danforth. “Having a mission statement to guide one’s giving can amplify the impact of charitable contributions, as well as boost the confidence donors have in their giving and the satisfaction they get from it. Moreover, charities can work together with these donors to meet long-term goals.”

Seventy-eight percent of donors know which charities they want to give to and 53 percent know how much they will give in the future, the survey of 1,042 Fidelity Charitable donors says.

However, only 22 percent have a mission statement or set of goals to guide their giving, according to the study. Women are more likely to have a plan for giving (27 percent) than men (19 percent).

Baby boomers plan to increase giving of their time, the study says, with 68 percent of full-time employees in their 50s planning to commit more time to philanthropy in the next five years, compared to 41 percent of all donors.

Fidelity Charitable is starting a two-month campaign, Boost Your Giving IQ, to share information on creating a charitable mission statement and selecting nonprofits that are aligned with the donors’ goals, among other topics.