中文摘要：

测试准则的有效性是软件质量保障的一个重要问题，但至今仍没有一个有效的度量方法．已有的度量对于全面表示测试效果、提高软件质量的作用非常有限．潜在失效距离（pfd）将测试准则对软件的测试有效性视为以规范、程序、缺陷类型和测试准则为自变量的函数，从软件和测试准则交互的角度来度量测试的有效性．与已有的度量相比较，该度量反映了软件经过满足测试准则的充分测试后获得的可靠性，为比较测试准则的测试效果提供了可行的方法，为设计更易测试的软件提供了指标．

英文摘要：

How to measure the effectiveness of test criterion is an important problem for software quality assurance. Till now, no consistent measures have been achieved. In this paper, potential failure distance （pfd） is proposed as an indication of the effectiveness of test criterion. It regards the effectiveness of test criterion on particular software as the function of specification, program, fault type and criterion. It proceeds measure from the point of interaction between software and test criterion. Compared with other related work, it reflects the achieved confidence on the correctness or reliability about the software after testing. The measure provides a feasible comparison of the effectiveness of test criteria on software. The measure can help to design more testable software.