"challenge to identify" is correct and usable in written English.
You can use it when you are asking someone to recognize, identify, or distinguish something from other things. For example, "This is a challenge to identify the message that was hidden in the coded document."
"It's a major challenge to identify the people who have died," Rajoy said.
It is a difficult challenge to identify the functional effects of protein acetylation in specific pathways.
Three designers have shared their spring 2013 mood boards with T. The challenge: To identify the images on each.
It has been a challenge to identify liver tumor suppressors or oncogenes due to the genetic heterogeneity of these tumors.
It has been a challenge to identify molecular classes of HCC and design treatment strategies for each specific subtype.
It has remained a challenge to identify selective neuroendocrine factors that stimulate body fat mobilization downstream of central mediators of energy balance, in any system.
It was an opportunity to stand out and a challenge to identify myself outside of the work I was so conditioned to seeing.
Despite the use of uterotonics agents as preventive measure, it remains a challenge to identify those women who are at increased risk of postpartum bleeding.
Policy makers are now facing the challenge to identify, apportion, and compare the determinants of regional tea expansion for designing more targeted political intervenes.
While hard failures are easy to identify – an application just stop working, it is a great challenge to identify reductions in service warranty fulfillment.
The availability of combinatorial chemistry and high-throughput screening has fueled the challenge to identify novel compounds that mimic nature's chemistry and to predict their macromolecular targets.
