Okay, let’s calculate. Hongfeng has full professional proficiency in English, which is a plus. Location is the Greater Seattle Area, which is a hub for tech companies. Machine Learning and Big Data are in high demand here. His skills in these areas are also in demand across industries. Considering his skills and location, I’d estimate his hourly rate to be around $125, which is slightly below average for someone with his skills in this area. This is because some senior data scientists with similar skills in the Seattle area can charge upwards of $200 per hour. However, Hongfeng’s skills and experience suggest he could charge around $150-$175 per hour, so I’ve rounded down to $125.