Languages like Scala and Go are benefiting from a tweaking of the Tiobe Index algorithm this month intended to eliminate spikes in rankings.

Tiobe assesses language popularity via a formula that analyzes searches in popular search sites, such as Google, Bing, Yahoo, and Wikipedia. The improved algorithm addresses the number of outliers -- "statistical noise" -- per search engine, Tiobe said in its monthly report for September.

[ Download InfoWorld's special report: "Extending the reach of enterprise developers." | Keep up with hot topics in programming with InfoWorld's Application Development newsletter. ]

"The previous algorithm focused on the number of outliers per search engine," according to the report. "If there were too many outliers for a search engine, that search engine would not qualify because of its 'untrusty' results. Now individual outliers (statistical noise per language per search engine) are removed. In this way, only the real outliers are gone, thus avoiding annoying spikes."

Languages like Java, with a 19.565 percent rating, and C with a rating of 15.621 percent, stayed in their usual places at the top of the index after implementation of the new algorithm, but some languages saw a jump and others dropped in the rankings. Scala moved up from the 33rd spot last month to 27th, with a .731 rating, and Go jumped to the 44th spot, with a rating of .254 percent, after having been ranked 95th last month.

Ada, with a rating of .792 percent, rose to the 23rd spot this month after being rated in the 30th spot in August. Rust, rated 50th with a rating of .198 percent, had been outside the top 50 languages last month, and Clojure is close to breaking into the top 50 as well, moving from 67th place last month to 52nd place. Julia made one of the biggest leaps, from 107th in August to 72nd in September.

Languages that dropped in this month's index included F#, which plummeted from 16th place last month to 32nd place, with a rating of .590 percent. OpenEdge ABL, ranked 21st in August with a rating of 1.005 percent, ranked 30th this month, with a rating of .635 percent.

Rounding out the top five in the index were C++ (6.782 percent), C# (4.909 percent) and Python (3.664 percent). In the rival PyPL Popularity of Programming Language Index, which analyzes how often language tutorials are searched on in Google, Java again took the top spot, with a 24.8 percent share, followed by PHP (11.3 percent), Python (11.2 percent), C# (9.2 percent) and C++ (7.6 percent) -- the same top five as last month.