The phrase "almost as effective" is correct and usable in written English.
It can be used to compare the effectiveness of two things, indicating that one is nearly as effective as the other.
Example: "While the new method is not perfect, it is almost as effective as the traditional approach."
Alternatives: "nearly as effective" or "practically as effective".
Transgene rescue experiments showed that a dCTCF protein lacking sequences critical for CP190 interactions was almost as effective as wild type in rescuing the phenotypic effects of a dCTCF null allele.
We found that a dCTCF protein lacking sequences critical for CP190 interactions was almost as effective as wild type in rescuing the phenotypic effects of a dCTCF null allele.
Contests are almost as effective as compensation plans when it comes to motivating the sales team.
Building a low annoying wall against them is almost as effective as building a high impenetrable one.
Based on an analysis of studies, the paper pronounced withdrawal "almost as effective as the male condom — at least when it comes to pregnancy prevention".
The success of "What's My Line?" inspired its makers, Mark Goodson and Bill Todman, to create a pair of knockoffs that were almost as effective as their model.
Many people are sure that exercise improves their mood, and studies have suggested that exercise is almost as effective as antidepressants in relieving symptoms of depression.
If this is the case then such a device can be almost as effective as a de-tuned neutralizer over quite a wide range of frequencies.
Tony Greaves Liberal Democrat, House of Lords As Saddam Hussein demonstrated, pretending to have a nuclear capability is almost as effective as actually having one, though it ended badly in his case.
Cardiologists have opened another front in the rancorous debate over expensive medical technologies, questioning the conclusions of a new study finding that high-resolution computer scans of the heart are almost as effective as conventional angiograms.
Friday's news that male contraceptive jabs are almost as effective as the female pill is remarkable as much for the lack of progress it highlights as for the impressive result the trial delivered.
