英语翻译Calculational Difficulties We do not wish to imply that

英语翻译
Calculational Difficulties
We do not wish to imply that constructing a value chain for a firm is easy.There are several thorny problems to confront:calculating a value for intermediate products,isolating key cost drivers,identifying linkages across activities,and computing supplier and customer margins.
The analysis starts by segmenting the chain into those components for which some firm somewhere does make a market,even ff other finns do not.This will catch the segments outlined in Exhibit 1 for the paper industry,for example.One could start the process by identifying every point in the chain at which an external market exists.This gives a good first cut at identifying the value chain segments.One can always find some narrow enough stage such that an external market does not exist.An example would be the progress of a roll of paper from the last press section of a paper machine to the first dryer section on the same machine.There is obviously no external market for paper halfway through a continuous flow paper machine!Thus,seeing the press section and the dryer section of the paper machine as separate stages in the value chain is probably not operational.
Part of the "art" of strategic analysis is deciding which stages in the value chain can meaningfully be decoupled conceptually and which cannot.Unless some firm somewhere has decoupled a stage by making a market at that stage,one cannot independently assess the economic profit earned at that stage.But the opportunities for meaningful analysis across a set of firms that have defined differently what they make versus what they buy and what they sell are often very significant.The fact that this is not always possible does not,in our view,negate the significance when it is possible..
Despite the calculational problems,we contend that every firm should attempt to estimate its value chain.Even the process of performing the value chain analysis,in and by itself,can be quite instructive.In our experience,we have found this exercise invaluable to managers by forcing them to carefully evaluate how their activities add value to the chain of customers who use their product (service).
We present below a case study from our field research (the name of the company and the financial data are disguised) which we believe illustrates the strategic power of a value chain analysis.

计算上的困难
我们绝不是说一个企业建立自己的价值链是一件容易的事情.企业会遇到各种棘手的问题：计算中间产品的价值,隔绝关键成本来源,辨别各种活动间的联系,以及计算供应商和顾客保证金.
分析要从将价值链细分为各种活动开始.这些活动是某些公司在某处的市场,是其它法国人和芬兰人都不曾进军的市场.造纸业的展品一号就符合上述细分概述.我们可以通过辨别外部市场上存在的价值链的每一点来开始这个过程,这是辨别价值链细分的良好的第一部.我们可以找到一些外部市场没有涉及到的小舞台.这个过程的其中一个例子就是卷纸,它从最后压纸阶段到最初的风干阶段,都是在同一台造纸机上进行的.世上当然没有外部市场,是专门为造纸流水线上半路出来的纸张而设的.所以,将压纸和干纸视为价值链的不同阶段是无法运作的.
决定价值链中的那些环节可以概念上分离,而哪些不可以,同样是战略分析的部分艺术.除非某些地方的某些公司分离出某些阶段并在那个阶段上发展市场,否则我们是无法独立估量那个阶段所创造的经济利润.但是,跨公司明确分析他们对制造、购买、销售的不同定义,这个机会也是十分重要的.在我们的观念中,这好像不可能,但事实是当它可能时,它的重要性是不可否认的.
虽然有计算问题,但我们仍主张每个公司都应评估其价值链.即使是执行价值链分析本身,也十分有益.在我们的试验中,我们强迫经理们去评估他们的活动是如何为使用他们产品/服务的顾客链增加价值的,发现这项活动对经理们十分宝贵.
我们现在在自己的研究领域（公司名称和财务数据化名）做一个案例研究,我们相信这个研究能展示价值链分析的战略意义.
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因为不知道这个论文有什么背景
所以第二段翻译得不够好
请楼主根据具体实际情况进行润色和修改