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#author("2019-01-21T19:13:23+09:00","","") #author("2019-01-22T08:06:39+09:00","","") [[論文英語単語帳/表現集]] ***リンク [#f20ebad6] #ls2(論文英語単語帳/) *** 表現集[#s089e92b] #ls2(論文英語単語帳/表現集/) *Implications [#w24ac55b] *推奨する [#a2e6311c] **推奨する [#a2e6311c] -recommend --The main implication of these findings is that, rather than recommending that size should always be controlled when building prediction models, we recommend that one should consider controlling for size only when significant evidence of mediation or moderation effects is observed, and that should be tested for each system individually. -advocate --We therefore recommend that if evidence of a significant mediation or moderation effect of size is found (which, as this paper advocates, should be examined using robust statistical methods), then one should consider controlling for size before looking at the prediction power of other OO metrics. In such cases, failing to control for size might result in models that are unstable and misleading in interpreting the prediction power of OO metrics. *Threat to validity [#t6b3930f] **Internal validity (内的妥当性)[#tb57ab24] ***定義 [#x195dbd2] -https://mumu.jpn.ph/forest/computer/2016/04/13/3302/#toc2 --定義１：１つの比較研究の”内”部における”比較の質”のことである。 --定義２：独立変数xと従属変数yの間に因果関係があると主張する研究における、その主張が持つ説得力の程度である。 --因果関係の存在を主張しようとするタイプの研究における研究の質を表す概念である。 --比較研究では、比較したい説明変数以外の全ての説明変数が、比較される各群間に均等に配分されている状態が最も望ましい。内的妥当性が高いとは、実際の比較研究がこの状態に近いことを意味する。 ***例 [#ya1bed24] -Internal validity threats concern factors that may affect a dependent variable and were not considered in the study. We paid attention not to violate the assumptions of the statistical tests that are performed in the paper. Specifically, in RQ1 and RQ2, we applied non-parametric tests that do not require making assumptions on the distribution of our dataset. -Threats to internal validity have to do with whether other plausible hypotheses could explain our results. We assume that fluctuations in the performance and impactful properties of JIT models are linked with fluctuations in the nature of fix-inducing changes. However, other intangible confounding factors could be at play (e.g., changes to team culture, contributor turnover). On the other hand, we con- trol for six families of code change properties that cover a broad range of change characteristics. Our findings may be specific to nonlinear logistic regression models, and may not apply to other classification techniques. As suggested by our prior work [8], we are actively investigating other classification techniques like Random Forest. Preliminary results indicate that the findings of RQ1 can be reproduced in the Random Forest context. However, since the Wald χ2 importance scores are not well-defined for such classifiers, a common importance score needs to be identified before RQ2 and RQ3 can be replicated. **External validity [#xfde7cee] ***定義 [#g41da06f] --ある研究の結果結果が、どの程度広い標的集団に適応できるかを示す概念である。 ***例 [#f19dc0fd] -External validity threats are concerned with the generalizability of our results. In this paper, we only studied Mozilla Firefox. First, Mozilla Firefox is the most studied system for issues related to rapid releases; moreover, the system’s data are publicly available. We also have the opportunity to per- form both quantitative and qualitative analyses (including the interviews with release managers) on this system. However, we should recognize that our findings may not be generalizable to other systems. In the future, we plan to collaborate with other software organizations, to validate and extend the results of this work. In addition, more studies on other systems with other programming languages are suitable to further validate our results. To facilitate future replication studies, we share our datasets and scripts at: https://github.com/swatlab/uplift- analysis. -Threats to external validity have to do with the generalizability of our results to other systems. We focus our study on two open source systems. We chose strict eligibility criteria, which limits the systems that are available for analysis (see Section 3.1). Due to our small sample size, our results may not generalize to all software systems. However, the goal of this paper is not to build a grand theory that applies to all systems, but rather to show that there are some systems for which properties of fix-inducing changes are fluctuating. Our results suggest that these fluctuations can have a large impact on the performance of JIT models and the quality improvement plans that are derived from JIT models. Nonetheless, additional replication studies are needed to generalize our results. **Contractual validity (構成概念妥当性) [#e4f746ca] ***定義 [#da5b0a23] -http://jspt.japanpt.or.jp/ebpt_glossary/constructvalidity.html --ある評価法が，測定しようとする概念や特性をどれだけ適切に反映しているかを意味します．言い換えると，全体的に見て個々の因子を組み合わせたとき，測定項目全体が意図するものを測っているかどうかに関する妥当性のことをいいます．たとえば，高齢者の転倒リスクの評価を行う場合，柔軟性，筋力，持久性，バランス，認知機能など関連性のある複数の因子を組み合わせることで，構成概念妥当性を高くすることができます． ***例 [#a417b5c7] -Construct validity threats are concerned with the relation- ship between theory and observation. Previous studies [19], [8] suggested that complex code is a good indicator of fault- proneness. We confirm this point in this study. However, we found that fault-inducing patches are more likely to be submitted by experienced developers, which contradicted our expectations. We attribute this outcome to the fact that ex- perienced developers are often assigned to difficult issues, whose resolution tend to be more complex. Also, release managers might overlook risks associated to patches submitted by experienced developers, as these developers are often more trusted than others.
