The Horsfall-Barratt scale and severity estimates of citrus canker

Bock, Clive H.; Gottwald, T. R.; Parker, P. E.; Cook, A. Z.; Ferrandino, Francis J.; Parnell, Stephen; Bosch, Frank van den

doi:10.1007/s10658-009-9455-x

Cited by 47 publications

(53 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Under some circumstances, category scales might even reduce the accuracy and reliability of individual assessments (4,5,8,11,13,(18)(19)(20)(21). Under some circumstances, category scales might even reduce the accuracy and reliability of individual assessments (4,5,8,11,13,(18)(19)(20)(21).…”

mentioning

confidence: 99%

Pecan Scab Severity—Effects of Assessment Methods

2013

View full text Add to dashboard Cite

Bock, C. H., Wood, B. W., and Gottwald, T. R. 2013. Pecan scab severity-Effects of assessment methods. Plant Dis. 97:675-684.Pecan scab is caused by the fungus Fusicladium effusum, and is the most destructive disease of pecan in the United States. Accurate and reliable disease assessments are needed to ensure that data provide a measure of actual disease intensity. The Horsfall-Barratt (H-B) category scale and its derivatives are commonly used to assess disease. Estimates using the H-B scale were compared with nearest percent estimate (NPEs) for rating disease severity of pecan scab on valves of fruit. Both inexperienced and experienced raters were included in the experiment. Lin's concordance correlation showed that agreement using NPEs was variable (pj. = 0.57 to 0.96), whereas estimates of disease severity using the H-B scale had similar agreement among most raters (p,, = 0.59 to 0.98). Converted values of NPEs to the H-B midpoints (NPEH-B) also provided a similar range (p^ = 0.61 to 0.96). Neither experienced nor inexperienced raters were consistently better using any of the three methods. Bootstrap analysis indicated that, among experienced raters, precision (r) and agreement (pj were often reduced when using the H-B scale compared with NPEs. There was no consistent effect of converting NPEs to NPEH-B midpoint values compared with actual H-B values. Inter-rater reliability using the H-B scale was never better than NPEs. Bootstrap analysis indicated no difference in the length of time needed to assess disease but regression analysis suggested that raters who were inherently last in assessing disease with NPEs were often slower when using the H-B scale; conversely, raters who were slow assessing with NPEs were often faster when using the H-B scale. Thus, there appears to be no advantage in accuracy or reliability or reduction in titne when inexperienced or experienced raters used a category rating scale to assess pecan scab.

show abstract

mentioning

confidence: 99%

Pecan Scab Severity—Effects of Assessment Methods

2013

View full text Add to dashboard Cite

show abstract

“…These nonlinear scales have been questioned and recent data provide evidence that they do not improve accuracy or reliability of assessments compared with NPEs, and may reduce the accuracy and precision of individual assessments (3,4,9,11,16,(21)(22)(23)25). Furthermore, expedments confirmed that estimates of disease are linearly related to actual disease (7,22,24).…”

mentioning

confidence: 99%

The Effect of Horsfall-Barratt Category Size on the Accuracy and Reliability of Estimates of Pecan Scab Severity

et al. 2013

View full text Add to dashboard Cite

Bock, C. H., Wood, B. W., van den Bosch, F., Parnell, S., and Gottwald, T. R. 2013. The effect of Horsfall-Barratt category size on the accuracy and reliability of estimates of pecan scab sevedty. Plant Dis. 97;797-806.Pecan scab (Pusicladium effusum) is a destructive pecan disease. Disease assessments may be made using interval-scale-based methods or estimates of sevedty to the nearest percent area diseased. To explore the effects of rating method-Horsfall-Barratt (H-B) scale estimates versus nearest percent estimates (NPEs)-on the accuracy and reliability of sevedty estimates over different actual pecan scab sevedty ranges on fruit valves, raters assessed two cohorts of images with actual area (0 to 6, 6+ to 25%, and 25+ to 75%) diseased. Mean estimated disease within each actual disease sevedty range varied substantially. Means estimated by NPE within each actual disease sevedty range were not necessarily good predictors of the H-B scale estimate at <25% sevedty. H-B estimates by raters most often placed severity in the wrong category compared with actual disease. Measures of bias, accuracy, precision, and agreement using Lin's concordance correlation depended on the range of actual sevedty, with improvements increasing with actual disease sevedty category (from 0 to 6 through 25* to 75%); however, the improvement was unaffected by the H-B assessments. Bootstrap analysis indicated that NPEs provided either equally good or more accurate and precise estimate of disease compared with the H-B scale at sevedties of 25+ to 75%. Inter-rater reliability using NPEs was greater at 25+ to 75% actual disease sevedty compared with using the H-B scale. Using NPEs compared with the H-B scale will more often result in more precise and accurate estimates of pecan scab sevedty, particularly when estimating actual disease sevedties of 25+ to 75%.

show abstract

“…Canker on Tabtimsiam pummelo growing at Pak Panang Basin, Nakhon Si Thammarat province was evaluated using visual estimation scale modified from Horsfall-Barratt and James [9] [10] [11]. The trees were category into 3 -5 and 6 -8-year age plant.…”

Section: Occurrence Of Canker Disease On Tabtimsiam Pummelomentioning

confidence: 99%

“…Canker disease severity on leaves and mature fruits. Disease severity score on leaf was measurement scale for visual estimation modified based on Horsfall-Barratt [9] [10] [11]. Disease severity was rated into 5 categories: 0, 5, 15, 25%, and 50% infection leaf area.…”

Section: Occurrence Of Canker Disease On Tabtimsiam Pummelomentioning

confidence: 99%