Phibbs C S, Luft H S
VA Medical Center, Menlo Park, CA 94025, USA.
Med Care Res Rev. 1995 Nov;52(4):532-42. doi: 10.1177/107755879505200406.
Studies of hospital demand and choice of hospital have used straight line distance from a patient's home to hospitals as a measure of geographic access, but there is the potential for bias if straight line distance does not accurately reflect travel time. Travel times for unimpeded travel between major intersections in upstate New York were compared with distances between these points. The correlation between distance and travel time was 0.987 for all observations and 0.826 for distances less than 15 miles. These very high correlations indicate that straight line distance is a reasonable proxy for travel time in most hospital demand or choice models, especially those with large numbers of hospitals. The authors' outlier analyses show some exceptions, however, so this relationship may not hold for studies focusing on specific hospitals, very small numbers of hospitals, or studies in dense urban areas with high congestion and reliance on surface streets.
关于医院需求和医院选择的研究，已将患者住所到医院的直线距离用作地理可达性的衡量指标，但如果直线距离不能准确反映出行时间，则可能存在偏差。对纽约州北部主要十字路口之间畅通无阻的出行时间与这些点之间的距离进行了比较。所有观测值的距离与出行时间之间的相关性为0.987，距离小于15英里时的相关性为0.826。这些非常高的相关性表明，在大多数医院需求或选择模型中，直线距离是出行时间的合理替代指标，尤其是那些涉及大量医院的模型。然而，作者的异常值分析显示了一些例外情况，因此对于关注特定医院、医院数量极少的研究，或在拥堵严重且依赖地面街道的密集城市地区进行的研究，这种关系可能不成立。
