施測者內信度(Intra-rater reliability)

Intra-rater reliability: The stability of data recorded by one observer across two or more trials of which the variables being rated are fixed and time is the only factor that varies between administrations.
施測者內信度指的是：一位評估者評估同一位個案兩次以上所得資料之穩定性。時間為影響施測結果的唯一變異因素。

Reference:
Brink Y, Louw QA. Clinical instruments: reliability and validity critical appraisal. Journal of evaluation in clinical practice 2011

標準:
可使用組內相關係數(intraclass correlation coefficient, ICC)來驗證。ICC值≧0.75代表具有良好的施測者內信度。

研究設計: 由一位評估者評估同一個案兩次或以上，兩次評估間隔的時間通常較短，如一個星期之內，而評估的個案能力/特質需不隨時間產生變化。
Reference:
Kruitwagen-van Reenen ET, Post MW, Mulder-Bouwens K, Visser-Meily JM. A simple bedside test for upper extremity impairment after stroke: validation of the Utrecht Arm/Hand Test. Disability and rehabilitation 2009;31:1338-1343.

Model paper:
Thornton M, Sveistrup H. Intra- and inter-rater reliability and validity of the Ottawa Sitting Scale: a new tool to characterise sitting balance in acute care patients. Disability and rehabilitation 2010;32:1568-1575.

臨床意義: 施測者內信度越高，代表評估工具評估個案能力/特質的結果越精確。