Evaluating Population Forecast Accuracy: A Regression Approach Using County Data

Forecast accuracy, Regression models, Panel data, Counties,

Transcatheter Aortic Valve Replacement in Low-Population Density Areas Assessing Healthcare Access for Older Adults With Severe Aortic Stenosis

Background: Restricting transcatheter aortic valve replacement (TAVR) to centers based on volume thresholds alone can potentially create unintended disparities in healthcare access. We aimed to compare the influence of population density in state of Florida in regard to access to TAVR, TAVR utilization rates, and in-hospital mortality. Methods and Results: From 2011 to 2016, we used data from the Agency for Health Care Administration to calculate travel time and distance for each TAVR patient by comparing their home address to their TAVR facility ZIP code. Travel time and distance, TAVR rates, and mortality were compared across categories of low to high population density (population per square miles of land). Of the 6531 patients included, the mean (SD) age was 82 (9) years, 43% were female and 91% were White. Patients residing in the lowest category (<50/square miles) were younger, more likely to be men, and less likely to be a racial minority. Those residing in the lowest category density faced a longer unadjusted driving distances and times to their TAVR center (mean extra distance [miles]=43.5 [95% CI, 35.6–51.4]; P <0.001; mean extra time (minutes)=45.6 [95% CI, 38.3–52.9], P <0.001). This association persisted regardless of the methods used to determine population density. Excluding uninhabitable land, there was a 7-fold difference in TAVR utilization rates in the lowest versus highest population density regions (7 versus 45 per 100 000, P -for-pairwise-comparisons <0.001) and increase in TAVR in-hospital mortality (adjusted OR, 6.13 [95% CI, 1.97–19.1]; P <0.001). Conclusions: Older patients living in rural counties in Florida face (1) significantly longer travel distances and times for TAVR, (2) lower TAVR utilization rates, and (3) higher adjusted TAVR mortality. These findings suggest that there are trade-offs between access to TAVR, its rate of utilization, and procedural mortality, all of which are important considerations when defining institutional and operator requirements for TAVR across the country

Empirical Prediction Intervals for County Population Forecasts

Demography, Small areas, Population projections, Forecast uncertainty, Accuracy,

Population forecast accuracy: does the choice of summary measure of error matter?

Population projections are judged primarily by their accuracy. The most commonly used measure for the precision component of accuracy is the mean absolute percent error (MAPE). Recently, the MAPE has been criticized for overstating forecast error and other error measures have been proposed. This study compares the MAPE with two alternative measures of forecast error, the Median APE and an M-estimator. In addition, the paper also investigates forecast bias. The analysis extends previous studies of forecast error by examining a wide range of trend extrapolation techniques using a dataset that spans a century for a large sample of counties in the US. The main objective is to determine whether the choice of summary measure of error makes a difference from a practitioner’s standpoint. The paper finds that the MAPE indeed produces error values that exceed the robust measures. However, except for situations where extreme outliers rendered the MAPE meaningless, and which are rare in real world applications, there was not a single instance where using an alternative summary measure of error would have led to a fundamentally different evaluation of the projections. Moreover, where differences existed, it was not always clear that the values and patterns provided by the robust measures were necessarily more correct than those obtained with the MAPE. While research into refinements and alternatives to the MAPE and mean algebraic percent error are worthwhile, consideration of additional evaluation procedures that go beyond a single criterion might provide more benefits to producers and users of population forecasts. Copyright Springer Science+Business Media B.V. 2007Forecast accuracy, MAPE, Error measures, Population projections,