The most significant limitation of the sampling methodology in which a hospital collects patient satisfaction data by mailing surveys to discharged patients is the potential non-representativeness of the respondents. This can lead to biased results because:

Response Bias: The patients who choose to respond to the survey may have different experiences or opinions compared to those who do not respond. For example, individuals with very positive or very negative experiences may be more motivated to complete and return the survey, while those with neutral experiences may not bother to respond. This creates a response bias.

Nonresponse Bias: If a significant portion of the patient population does not respond to the survey, the data collected may not accurately reflect the overall patient satisfaction. This can result in an overestimation or underestimation of patient satisfaction levels, leading to incorrect conclusions and potentially flawed quality improvement strategies.

Sampling Bias: Since the survey is voluntary, there is no guarantee that the sample of respondents is representative of the entire discharged patient population. Factors such as age, literacy, socioeconomic status, and health condition might influence who responds, further skewing the results.

Impact on Data Validity: The lack of representativeness can compromise the validity of the findings. Decision-makers relying on these survey results may implement changes based on incomplete or biased information, which might not address the needs or concerns of the broader patient population.