How would you detect fake reviews using machine learning?

Focus on outlining a clear approach to detecting fake reviews through machine learning techniques. Start by identifying the types of data you would collect, such as review text, user behavior, and metadata. Discuss specific machine learning models you might use, like natural language processing for text analysis and anomaly detection for user behavior patterns. Consider the importance of feature engineering and how you would define features that indicate authenticity or deception. Finally, address potential challenges, such as dealing with biased data or adapting to evolving tactics used by those writing fake reviews.