Dahlberg formula: a novel approach for its evaluation

Abstract

INTRODUCTION: The accurate evaluation of error of measurement (EM) is extremely important as in growth studies as in clinical research, since there are usually quantitatively small changes. In any study it is important to evaluate the EM to validate the results and, consequently, the conclusions. Because of its extreme simplicity, the Dahlberg formula is largely used worldwide, mainly in cephalometric studies. OBJECTIVES: (I) To elucidate the formula proposed by Dahlberg in 1940, evaluating it by comparison with linear regression analysis; (II) To propose a simple methodology to analyze the results, which provides statistical elements to assist researchers in obtaining a consistent evaluation of the EM. METHODS: We applied linear regression analysis, hypothesis tests on its parameters and a formula involving the standard deviation of error of measurement and the measured values. RESULTS AND CONCLUSION: we introduced an error coefficient, which is a proportion related to the scale of observed values. This provides new parameters to facilitate the evaluation of the impact of random errors in the research final results

Penyerapan Akar Gigi Apeks Luaran Hasil Rawatan Ortodontik Pada Enam dan 12 Bulan

“…Pengukuran panjang gigi dilakukan sebanyak tiga kali. Nilai korelasi intra-kelas (ICC) diperoleh dengan menggunakan formula Dahlberg bagi menentukan kebolehpercayaan intra pemeriksa (Galvão et al 2012 HASIL PENYELIDIKAN Nilai ICC antara dua pengukuran panjang gigi ialah 0.95, dengan 95% selang keyakinan (CI). Ini menunjukkan tiada perbezaan antara kedua pengukuran panjang gigi oleh penyelidik.…”

Making Sense of Errors Made by Analytical Chemistry Students in Their Writing

“…This theory was conceptualised out of dissatisfaction with Contrastive Analysis (CA). The process involved in CA is the comparison of learners' mother tongue and the target language (Heydari & Bagheri, 2012) while Error Analysis analyses all sources of errors (Sanal, 2008). Unlike classical CA, Error Analysis suggests that the learners' learning strategies are the main causes of errors, namely: 'transfer', 'overgeneralisation', 'simplification', 'avoidance', and 'overproduction' (Zhuang, 2011).…”

Qualitative and quantitative evaluation of central incisor movement by integration of three-dimensional images of dental cast and cephalogram

“…In the second step, the Dahlberg formula was used to evaluate the error of measurement in the two measuring methods. The Dahlberg formula is defined as EM ¼ ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ffi P d 2 =2n q , where d is the difference between first and second measurements, n is the number of sample [16,17]. All measurements were performed by one examiner and repeated twice with an interval of two weeks.…”