The phrase "a decision which affected" is correct and usable in written English.
It can be used when discussing the impact or consequences of a specific decision on a situation or group of people.
Example: "The committee made a decision which affected the funding for several community projects."
Alternatives: "a decision that influenced" or "a decision that impacted".
"What's at stake here is the future of these islands – we're about to make a decision which affects them.
"In light of WWOR's decision to drop their nightly news programming, a decision which affects millions of New Jerseyans, it is becoming increasingly critical that the F.C.C. make a determination about WWOR's license and whether they are adequately serving New Jersey as the law and F.C.C. rules stipulate," Mr. Menendez wrote to Mignon L. Clyburn, the acting chair of the commission.
It will thrash out problems caused when the British government takes a decision which affects something which is the assemblies' responsibility, and will discuss the treatment of devolved matters in different parts of Britain.The proposed committee, assuming that the assemblies agree to it, will operate rather like the European Council of Ministers.
In the wake of the controversial decision, Mr Brown complained that the Scottish government was given no warning of a decision which affects the country.
He built an ashram, a commune which was home to "many a fateful decision which affected the destiny of India".
It was strictly a professional decision, which affected his work and nothing else.
The decision, which affected a number of other steamy apps, caused some consternation among developers--mostly because it reflected a sudden change in Apple's policy and cost the creators' money, since they'd been banking on revenue from apps that were no longer sellable.
The screening process serves to block dangerous or irresponsible candidates, but also underscores for applicants and their families that bringing home a gun is a serious decision which affects the entire household, and indeed the entire community.
Councillor Heenan said it was "an unfortunate" decision which affects the 300,000 people the hospital served.
In a series of related projects which began with my Ph.D. thesis, I have been analyzing the process by which Italian adolescent children and their parents make the choice of high school track, a consequential human capital decision which affects Italian students' future choices and outcomes in school as well as on the labor market.
