Title

How ribbiting! Intra and interobserver differences in measuring amphibian body length

Poster Number

9

Lead Author Major

Pre-Pharmacy

Format

Poster Presentation

Faculty Mentor Name

Hilton Oyamaguchi

Faculty Mentor Department

Biological Sciences

Abstract/Artist Statement

Measuring amphibians body size by different researchers and methods can lead to a lot of variation. Although this variation can result in different biological interpretations, very little attention has been paid to this measurement error. Our goal in this study was to access the error associated to repeated measurement made by the same researcher, between researchers, and between two methods. We used two methods to compare intra-observer and inter-observer differences in measuring amphibian body length: ImageJ software and manual measurement with a caliper. ImageJ software is an image processing software that can be downloaded for free and is widely used to display, analyze, edit, and process images. The caliper has a hand held instrument that researchers use to measure morphological traits (±0.01mm). Five researchers measured 32 adult specimens of the tungara frog (Engystomops pustulosus) and each specimen was measured three times with both measurement techniques. From our initial data analysis, using these two different methods to access body led to about 25% of measurement variation. About 15% of measurement variation is due to differences between researchers. Our results suggest that comparable and precise measurements of preserved frogs between different methods and different researchers is challenging. These differences can lead to error in biological interpretations. We are developing an automated measuring software to standardize these measurements and minimize inter-observer variation.

Location

DeRosa University Center, Ballroom

Start Date

25-4-2015 10:00 AM

End Date

25-4-2015 12:00 PM

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Apr 25th, 10:00 AM Apr 25th, 12:00 PM

How ribbiting! Intra and interobserver differences in measuring amphibian body length

DeRosa University Center, Ballroom

Measuring amphibians body size by different researchers and methods can lead to a lot of variation. Although this variation can result in different biological interpretations, very little attention has been paid to this measurement error. Our goal in this study was to access the error associated to repeated measurement made by the same researcher, between researchers, and between two methods. We used two methods to compare intra-observer and inter-observer differences in measuring amphibian body length: ImageJ software and manual measurement with a caliper. ImageJ software is an image processing software that can be downloaded for free and is widely used to display, analyze, edit, and process images. The caliper has a hand held instrument that researchers use to measure morphological traits (±0.01mm). Five researchers measured 32 adult specimens of the tungara frog (Engystomops pustulosus) and each specimen was measured three times with both measurement techniques. From our initial data analysis, using these two different methods to access body led to about 25% of measurement variation. About 15% of measurement variation is due to differences between researchers. Our results suggest that comparable and precise measurements of preserved frogs between different methods and different researchers is challenging. These differences can lead to error in biological interpretations. We are developing an automated measuring software to standardize these measurements and minimize inter-observer variation.