According to the book, “Pastor Russell – Founder of the Bible Students,” published by Bible Students Christian Classics:
Now that three quarters of the Bible Students of Pastor Russell’s era were purged and the remainder of the Bible Students submitted to the doctrinal changes, a new movement could be founded.
In 1931, fifteen years after Pastor Russell’s death, Jehovah’s Witnesses was founded. Its founder, Joseph Rutherford, presented a startling resolution entitled “A New Name,” which was adopted at their international convention on July 26, 1931. (See Addendum #9–Jehovah’s Witnesses Founded in 1931 by Joseph Rutherford.) The resolution first observed that neither “Russellites” nor “Bible Students” were any longer appropriate names (certainly not, since over 75 percent of Bible Students from Pastor Russell’s era had already separated themselves). Henceforth, Rutherford introduced, they would call themselves “Jehovah’s Witnesses.” Joseph Rutherford, not Pastor Russell, founded Jehovah’s Witnesses. Pastor Russell died in 1916. Jehovah’s Witnesses was founded in 1931. Pastor Russell founded the Bible Students who still affirm his teachings. Rutherford rejected Russell’s teachings, purged those Bible Students loyal to Russell’s ideals from his movement, rejected the name Bible Students and named his new movement “Jehovah’s Witnesses.”