A pervasive problem is the vulnerability of observational data to distortions and biases.
A pervasive problem is the vulnerability of observational data to distortions and biases.
另外，观察法最常见的问题为资料容易被曲解及有偏差。
A pervasive problem is the vulnerability of observational data to distortions and biases.
另外，观察法最常见的问题为资料容易被曲解及有偏差。