The phrase "have certainly contributed to" is correct and usable in written English.
You can use it when discussing the positive impact or influence of something on a particular outcome or situation.
Example: "The recent policy changes have certainly contributed to the improvement in employee morale."
Alternatives: "have undoubtedly played a role in" or "have positively impacted".
Not responding to it as effectively as we probably could have certainly contributed to it.
The wind and rain have certainly contributed to some of the erratic kicking, although England played Argentina in an indoor stadium in Dunedin.
High crude oil costs have certainly contributed to the rising prices, but so have jitters among fuel traders and service station owners who note that stocks of gasoline are below the historically low levels the country had last year.
Merkel, who is believed to have secured commitments that German job losses will be minimised, said an Opel sale to Magna was "the right decision" and though she stressed she had not lobbied the US government, she was happy to take much of the praise, adding: "The patience, purposefulness and clarity of the [German] government and myself have certainly contributed to this".
His short-term actions have certainly contributed to the establishment of a strongly anti-Russian government in Kiev.
I'm not sure how well that ever worked for 3G services, although consumer tastes for streaming media, and device specs, have certainly contributed to a more fertile ground for marketing and service bundles like these to work better this time around.
Ashok has certainly contributed to that".
But "global economic growth has certainly contributed to these developments," it said.
Tim Howard's goalkeeping has certainly contributed to the success of the MetroStars.
Gentrification over the past decade has certainly contributed to the increased cost of housing in Harlem.
"Restaurant sales are up 15 to 20percentt in the last year, and the Internet has certainly contributed to that," Mr. Menzel said.
