给网友查一些资料，供您体味。

用…衡童，从…看(judge多用分词形式）

➢ Judged by the ordinary standards, he was reliable. (Snow)

➢ Judged by immediate results the Chartists failed completely. (Hazen) 

➢ "Thirty years ago/he said/That's a lot of years judged by anybody's standards.  (CIH)

➢ Judging by the look on his face， he doesn't think much of our local wine. (CIE)

➢ I thought that, judging by the response of the audience, I had made an effective speech. (Pollitt)

➢ Judging by his testimonials, I think he will suit the post. (McMordie)

judge from从…看，根据…可以看出：

➢ From the finger marks high on the cupboard we can judge that he was a tall man. (CIE)

➢ To judge from the evidence of the experts, the deceased was still alive at three o'clock. (CIE)

➢ Judging from wha.t you say, he ought to succeed. (ALD)

➢ Judging from the number of cars, he thought, there were not many people at the club yet. (Greene)

以上例子出自 张道真《现代英语用法词典（重排本）》judge词条。

另外：《朗文高阶》有：

judging by / from sth, used to say that you are making a guess based on what you have just seen, heard, or learned

   依据〔所见、所闻或所学〕来判断:

   Judging by his jovial manner he must have enjoyed his meal.

   从他愉快的样子来看，他这顿饭肯定吃得很开心。

   Judging from what you say in your letter, you don't sound well.

   根据你来信中所写的情况，你听上去好像不大好。

      综上，大概可以得出这样的结论：

   1. judging.../to judge...的动作执行者，是说话人或写那句话的人，juding的结果就是主句所述内容。

   2. judged from...强调动作承认者是句子主语。比如Judged by the ordinary standards, he was reliable. (Snow) = If he was judged by the ordinary standards, he was reliable. (Snow) = If you judged him by  ordinary standards, (you could say)he was reliable. (Snow)  =Judging by the ordinary standards, he was reliable. (Snow) 

  3. 虽然有时候可以换，但未必“可以随意用”，主要看语境语义，还有就是语用习惯和语言接受度问题。因此，在考试时候，最好不要以身试法。

   希望以上回答对网友有用。