"has likely contributed" is a correct phrase and can be used in written English.
It is often used to express something that is probable or believed to have happened. Example: The increase in temperature has likely contributed to the decline of the polar bear population.
The paucity of animal studies has likely contributed to the slow progress in this area.
The recent increase in such hot days has likely contributed to the observed yield stagnation.
The B1G1 model holds a lot of intuitive appeal, which has likely contributed to its proliferation.
To the extent that housing wealth matters, however, the housing bust has likely contributed to a corresponding baby bust.
This massive movement of physician has likely contributed to health crises in many African nations, where citizens die of easily curable diseases each year.
These genes appear to be involved in important processes such as cell propagation, plant development and response to stress, and their up-regulation has likely contributed to influencing seedling growth patterns.
Meanwhile, drug companies' advertising campaigns helped push American doctors to prescribe painkillers at much higher rates than in other countries, a fact that has likely contributed to the country's growing epidemic of opioid addiction.
Likewise, a drastic decline in dense stands of giant cane (Arundinaria gigantea; hereafter: cane), a native bamboo often associated with Swainson's Warblers, has likely contributed to a decline in their range and numbers.
Likewise, the increasing acceptance of the liberal democratic model among citizens around the world following the fall of communism has likely contributed to authoritarian regimes' assessment that the adoption of democratic institutions is essential to maintaining domestic legitimacy.
This model has likely contributed to slower adoption for Rdio.
The robust reliability of this test has likely contributed to its popularity and widespread application.
