Training Effect on Decreasing Scoring Differences of Observers Using Visual-based Assessments of Stream habitat

我們利用一套美國建立的目視棲地評估系統，以國中及高中自然課程之教師為對象，驗證下列假說：利用目測決定溪流棲地品質時，人員如接受先期訓練，將可減低個人主觀所產生之誤差。研究方法為十四名進行棲地評估前已接受訓練和十名未受訓練的觀察員首先分別對一略受人為干擾溪段進行目視之棲地品質評定。結果顯示，先受訓練者較位受訓練之人員在最後總分及底土堆積、溪道流況及溪岸穩定性等三項棲地均給予在統計上顯著較高的分數。在接受同樣程度的訓練和累積相似的評估經驗後，兩組人員再同時對一受到人為干擾之溪段進行棲地狀況評估，結果發現第二次評估兩組間之總分、測項分數和分數的變異程度仍存在顯著差異。在美國進行之類似實驗則發現，以大學生為觀察者，僅需一次相同程度之訓練，由此研究之結果，再台灣地區對觀察人員進行目視溪流棲地評估之訓練時，我們建議應該對棲地結構與功能，提供特別詳細之說明，進行實地評估前，應確定評估人員瞭解評估項目之意義與給分標準。同時，受訓人員也應於訓練中累積評估不同人為干擾程度溪段之經驗，如此，未來方能建立較可靠且具比較性的溪流棲地資料庫。

關鍵字

訓練；目視評估；溪流棲地

並列摘要

We used a US-developed visual-based evaluation system to investigate the training effect in reducing differences of scores assigned by observers when they assessed the quality of a stream habitat. Fourteen observers received training before they conducted the habitat evaluation in a less-modified stream section, while another ten observers made the assessment without training. Compared to the untrained group, the pre-trained group assigned significantly higher total scores as well as higher grading for the three habitat attributes of sediment deposition, channel flow status, and bank stability. After equal levels of training and experience, scoring differences and variability were still present between the two groups when they assessed habitat quality in a human-modified stream section. We conclude that a detailed explanation of the theoretical basis and function of the habitat parameters, an examination to ascertain whether observers truly understand the grading system, and evaluation experience in a range of habitat types are crucial for conducting visual-based assessments of stream habitats.

並列關鍵字

Training ； visual assessment ； stream habitat

國際替代計量

Training Effect on Decreasing Scoring Differences of Observers Using Visual-based Assessments of Stream habitat

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