Scriven Model of Argumentation

Introduction	A Sample Argument	Step One	Step Two	Step Three
Step Four	Step Five	Step Six	Step Seven

Introduction

Michael Scriven, currently a professor of psychology at Claremont Graduate University, has impressive track record as a researcher in several areas including technology, evaluation sciences and critical thinking. In 1976, Scriven outlined his seven-step approach to argument analysis in his book Reasoning (New York : McGraw-Hill, 1976).

A Sample Argument

Each of the seven steps will be discussed in depth and then applied to the argument put forward in a letter written to the editors of the Toronto Star. This letter was written in response to a study published by Dr. Nancy Baxter and her colleagues in the Canadian Medical Association Journal. Of the study recommendations the most controversial states that routine teaching of breast self-examination (BSE) be excluded from the periodic health examination of women aged 40-69 as there is fair evidence of no benefit and good evidence of harm.

Jury’s out on self-exams

Re: Stop “useless” self-exams on breasts, women urged, June 26.

I agree with Dr. Larissa Nekhlyudov that it is premature to urge women to stop performing breast self-examination (BSE).

The conclusions reached after a dissenting voice from two Harvard doctors who were asked to review Dr. Nancy Baxter’s review of the literature are not acceptable.

I have read the Chinese and Russian studies, both of which are incomplete, lacking in detail and unfinished and, in the case of the Russian study, may never be completed.

Russia has been in a severe state of social and political unrest for at least the last five years.

Are we to expect Canadian women to accept this fragmented study from a country bordering on social chaos?

In both countries, the criteria for teaching and learning BSE and follow-up of practicing BSE has not been included in the studies.

Dr. Baxter also inappropriately states, “that those who did BSE had a greater risk for harm in terms of increased anxiety.” This is greatly overstated.

Tell me one person who goes for a blood test who is not anxious. Has the medical profession stopped doing blood tests.

A BSE examination is non-invasive, can be done in the privacy of one’s own home and creates a lot less anxiety then being diagnosed with breast cancer.

Dr. Baxter should speak with women who found their “lump” through practicing BSE and try to tell them it’s “useless”.

Dr. Baxter goes on to say that there is an increased rate of unnecessary biopsies for benign lumps.

Yes, there will be more biopsies. Eighty per cent of lumps found by women are benign.

It is a great comfort to women to know that under a local anesthetic in a very short procedure that the “lump” can be identified as malignant or benign.

BSE includes a number of simple steps, standing and lying down, looking at and examining the breasts, encouraging women to become familiar with their breasts so if a change is noticed they can follow up by visiting a health care professional.

Women in Canada are quite capable of learning correct breast self-examination.

BSE as an additional tool along with mammograms and a health professional breast examination does increase the chances of discovering breast cancer at an earlier and more easily treated stage.

Janet Dikland
President
Breast Cancer Action
Kingston

(Dikland J., Toronto, "Jury’s out on self-exams", The Toronto Star, June 30, 2001.)

Step One: Clarifying Meaning

The first step in the Scriven model of argument analysis involves clarifying meaning. You should begin this process by first reading the entire argument (or passage) under consideration. If you encounter any unknown terms refer to a dictionary and replace them. Parts of the argument that use unclear language or vague terms should also be rewritten with clearer language that conveys the correct meaning (within the appropriate context). While reviewing the argument you may notice that there are many important but yet unstated premises, inferences and conclusions. You should make note of these and perhaps write these down somewhere as they will be important in Step Two. By the end of Step One you should have a feeling of what the argument is trying to get across and how things fit together.

Step Two: Identify Conclusions

Before attempting to identify conclusions it is important to realize that an argument may contain several conclusions with conclusions potentially building upon one other. Having clarified meaning in Step One, now look for explicitly stated conclusions. While there is no simple stepwise procedure that can be followed in identifying such conclusions indicator words and positional cues may help. For example, conclusions often begin with words like “therefore”, “because” and “thus” and are placed towards the end of paragraphs.

You may have identified some unstated conclusions in Step One while clarifying meaning. Review the argument once again and try to find any additional unstated conclusions. Having done this write them down under the passage or where they come in the argument.

After identifying both the stated and unstated conclusions you should decide which one is the main conclusion and rank the importance of the remaining conclusions.

In the letter to the Toronto Star the main conclusion is that it is premature to urge women to stop performing breast self-examination (BSE). Other conclusions include the following:

The findings of the Chinese and Russian studies are not applicable to Canadian society.
The risk of increased anxiety from BSE is overstated.
Women have found lumps through practicing BSE and therefore it is not “useless”.
BSE helps increase the chances of early diagnosis and intervention.

Step Three: Portray Structure

This step involves visually setting out the relationships between the premises and conclusions in the argument. Having identified conclusions in Step Two we now need to locate the assertions, named premises, that are put forward in support of conclusions.

Number each premise and conclusion (both stated and unstated) you find in the passage. In the case that a single sentence has multiple premises, demarcate each premise with square brackets and number it appropriately. A number should not be assigned to premises that are repeated or to irrelevant statements.

For example,

{1} [I agree with Dr. Larissa Nekhlyudov that it is premature to urge women to stop performing breast self-examination (BSE).]

{2} The conclusions reached after a dissenting voice from two Harvard doctors who were asked to review Dr. Nancy Baxter’s review of the literature are not acceptable.]

{3}[I have read the Chinese and Russian studies, both of which are incomplete, lacking in detail and unfinished and, in the case of the Russian study, may never be completed.]

{4} [Russia has been in a severe state of social and political unrest for at least the last five years.]

{5 – Unstated Conclusion} [The findings of the Russian and Chinese studies are not applicable to Canadian women.]

Are we to expect Canadian women to accept this fragmented study from a country bordering on social chaos?

{6} [In both countries, the criteria for teaching and learning BSE and follow-up of practicing BSE has not been included in the studies.]

{7 – Unstated Conclusion} [The conclusion of Dr. Baxter’s study that the routine teaching of BSE be excluded from the periodic health examination of women aged 40-69 as there is fair evidence of no benefit and good evidence of harm is invalid.]

{8} [Dr. Baxter also inappropriately states, “that those who did BSE had a greater risk for harm in terms of increased anxiety.” This is greatly overstated.]

Tell me one person who goes for a blood test who is not anxious. Has the medical profession stopped doing blood tests.

{9} [A BSE examination is noninvasive, can be done in the privacy of one’s own home and creates a lot less anxiety then being diagnosed with breast cancer.]

{10} [Dr. Baxter should speak with women who found their “lump” through practicing BSE and try to tell them it’s “useless”.]

Dr. Baxter goes on to say that there is an increased rate of unnecessary biopsies for benign lumps.

Yes, there will be more biopsies. Eighty per cent of lumps found by women are benign.

{11} [It is a great comfort to women to know that under a local anesthetic in a very short procedure that the “lump” can be identified as malignant or benign.]

{12} [BSE includes a number of simple steps, standing and lying down, looking at and examining the breasts, encouraging women to become familiar with their breasts so if a change is noticed they can follow up by visiting a health care professional.]

Women in Canada are quite capable of learning correct breast self-examination.

{13} [BSE as an additional tool along with mammograms and a health professional breast examination does increase the chances of discovering breast cancer at an earlier and more easily treated stage.]

The relationships between the premises, conclusions and arguments will be set out in a tree-diagram similar to the one shown to the right. In the sample diagram (which has nothing to do with the letter we are analyzing), 1 and 2 are claims put forward in support of 3 (a conclusion) which then goes on to support 4 (an unstated conclusion). By convention, unstated conclusions are placed within parentheses.

While constructing a tree diagram look for places in the argument where there are important, unstated assumptions (premises). Place a circle in the appropriate place in the tree diagram and use a letter rather than a number. The method used to formulate unstated premises will be outlined in Step Four.

Applying what we have learned so far to the letter we are analyzing:

The above tree diagram shows that there are several sub-arguments put forward in the argument. These sub-arguments focus on the following issues:

The validity of the Russian and Chinese studies
The study exaggerates the amount of anxiety associated with BSE
BSE is not useless as it has found breast lumps in many women
The value of BSE in early detection and better outcomes

Step Four: Formulate Unstated Assumptions

Formulating fair and clear “missing premises” is regarded as the most difficult part of reconstructing an argument. You should aim to find what Scriven describes as “optimal assumptions”, those claims which are both logically adequate and independently well supported.

Three unstated assumptions were identified while portraying structure in Step Three.

Assumption a:	Potential differences in teaching, learning and practicing BSE in Russia and China could limit the applicability of any BSE study findings from those countries to Canadian women.

Assumption b:	BSE makes women less anxious since they feel more aware and in control of what is happening with their bodies.

Assumption c:	The fact that some women have found lumps in their breasts through BSE is some evidence for the usefulness of BSE.

Step Five: Criticize Inferences and Premises

Criticizing an inference involves criticizing the claim that one statement supports another (e.g. statement 2 follows from statement 1). What is important is not the actual truth of statement 1 but rather if it were true would statement 2 have to be true (or at the very least be likely to be true).

For an argument to be effective it should gather support from reliable premises. Scriven suggests that you focus your efforts on assessing definitions and analysis subject to logical criticism and matters of common knowledge. Avoid spending time on assessing technical claims.

You must evaluate the reliability of both the inferences and premises of an argument. Focusing your efforts on one of them may expose you to counterattack if you made an error in your criticism or if your criticism can be easily met by minor modifications on the part of the arguer. You should be selective in the ways you criticize an argument. Initially focus on the main conclusion and the premises and inferences that support it. Start with any key weaknesses and use your strongest criticisms. Strong criticisms are those that can’t be met by the arguer expect by major modifications to the argument or capitulation.

A strategy that you may employ in criticizing an argument is “counter-exampling”. Try to find cases where generalizations, definitions and inferences employed in the argument don’t hold.

Our reconstruction of the argument through the addition of missing premises and conclusions will show areas in which the argument required some bolstering before it could be considered to have good structure. The premises we added may have been necessary to make the argument “work” but they may not be true and are therefore potential sites of criticism.

In premise #2 the letter refers to the opinions of two Harvard doctors about Dr. Baxter’s literature review as support for rejecting the findings of the study. However, before we can accept expert opinion we should ensure the following:

This is a matter that only experts can understand.
Is the authority we are citing truly an expert?
Is there any bias towards one side?
Is the authority’s opinion representative of expert opinion?

If an argument cannot fulfill any of the above mentioned points then the argument may commit the fallacy known as "Appeal to Authority".

The problem with the arguments about the Chinese and Russian studies (Premises 3-6) is the unstated assumption about relevance. For her to make her case, she needs an additional argument. We urge you to read the Chinese and Russian studies and apply the critical appraisal framework. This should help exercise your own independent judgment and hone your critical skills.

Premises #12 and #13 form the sub-argument that BSE is a useful screening tool and improves patient outcomes. After reading this part of the letter one gets the impression that the writer has not understood Dr. Baxter’s study. The study recommendation is based on evidence from other studies that BSE does not improve patient outcomes (i.e. mortality) in those who practice it versus those who don’t. If BSE is ineffective in reducing mortality then it may unnecessarily increase anxiety in those who find lumps while practicing it. This is the basis for the study finding that there is good evidence of harm for the use of BSE.

While it is undoubtedly true that many women have found lumps using BSE (Premise #10), one still has to ask if finding a breast lump with BSE has improved patient outcomes. For example, finding a lump with BSE doesn’t necessarily mean that a cancer is at earlier stage or more easily treated. This is exactly the matter at issue.

Step Six: Consider Other Relevant Arguments

Steps one through five have allowed us to critique the argument under consideration. If we were to stop here we would be limiting ourselves to a Stage Two (i.e. one-sided) argument. Just because an argument has defects does not allow us to dismiss it outright. There may be some weight in the argument and perhaps enough for one to act on.

Step Six involves stepping back in order to get a better perspective of the argument. We need to consider other relevant arguments? Are there any arguments on the very same issue with different conclusions? Are there any that support the same conclusion? This step should help you figure out what you think about the issue.

The most relevant counter argument here is the Baxter study itself.

Step Seven: Overall Evaluation

Review the criticisms you have made of this argument. Could the arguer meet your criticisms through modest modifications of the original argument? Have you covered all the lines of argument? Consider the results of Step Six.

Make a final judgment on the argument and assign it an overall grade. Having done this you should now determine how much force this argument has and how successful it has argued its position. This is for you to decide.