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	<title>Statistical &#38; Scientific Thinking</title>
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	<link>http://jsdstat.com/Statblog</link>
	<description>Using principles of Science and Statistical Thinking in Policy</description>
	<pubDate>Wed, 19 Nov 2008 06:05:15 +0000</pubDate>
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		<title>The Deming Chain Reaction</title>
		<link>http://jsdstat.com/Statblog/2008/11/08/the-deming-chain-reaction/</link>
		<comments>http://jsdstat.com/Statblog/2008/11/08/the-deming-chain-reaction/#comments</comments>
		<pubDate>Sat, 08 Nov 2008 22:02:44 +0000</pubDate>
		<dc:creator>John</dc:creator>
		
		<category><![CDATA[Statistical Thinking]]></category>

		<guid isPermaLink="false">http://jsdstat.com/Statblog/?p=135</guid>
		<description><![CDATA[The so-called Deming Chain Reaction was actually borrowed from a model that Walter Shewhart developed.  He probably borrowed the idea from another thinker.  Basically the idea was for management to move away from thinking about quality as a desirable outcome, to thinking about quality as a competitive strategy.

Competitive strategy as a concept has been around [...]]]></description>
			<content:encoded><![CDATA[<p>The so-called Deming Chain Reaction was actually borrowed from a model that <a title="Shewhart" href="http://en.wikipedia.org/wiki/Walter_Shewhart">Walter Shewhart</a> developed.  He probably borrowed the idea from another thinker.  Basically the idea was for management to move away from thinking about quality as a desirable outcome, to thinking about quality as a competitive strategy.</p>
<p><span id="more-135"></span></p>
<p>Competitive strategy as a concept has been around for centuries.  A person selling an item similar to that sold by another can compete on price, by selling it for less money.  Perhaps the seller may try to compete by adding extras, gift-wrapping, for example.  Technical companies compete by being technology leaders and being on the cutting edge of new developments.  There are no end to methods to compete.  But some methods are more effective in the long run than others.</p>
<p>It is not a mistake that Deming&#8217;s first published book on the subject was entitled &#8220;On Quality, Productivity and Competitive Position&#8221;.  In the book, he sets forth the reasons why emphasis on quality leads to productivity improvement and how that is a very effective competitive strategy in the long run.  Phil Crosby in the early 80s in his book, &#8220;Quality is Free&#8221; pointed out that improving quality lowered cost.  But Deming had shown this to the Japanese  30 years earlier.  And, Deming pointed out the benefits of developing a competitive strategy based on quality.</p>
<p>One of the problems in talking about quality is that many people have pre-conceived notions of quality is.  For some it is meeting specifications.  Joseph Juran defines it as &#8216;meeting customer requirements&#8217;.  Zero Defects was Crosby&#8217;s nostrum, but is really just another way of saying quality is meeting specfications.</p>
<p>Deming&#8217;s ideas are much broader than that and are, perhaps, best captured with the phrase &#8216;continual improvement&#8217;.  This term connotes the ongoing nature of the strategy.  According to Deming, quality is not a state to be achieved in manufacturing, but is, rather, an ongoing company-wide effort at continual improvement.  What Bill Conway called &#8220;the process - the way everyone thinks, talks, works and acts every day.&#8221;</p>
<p>Whether or not this is a successful strategy is, in my opinion, not arguable.  One has only to look at the automobile industry for clear proof.  After all the nonsense is stripped away, the fact is that Japanese automakers (Toyota, Honda and Nissan) make better cars than American automakers (GM, Ford and Chrysler) and have done now for years.  Buyers are not idiots.  They understand value, and and realize that better quality at the same or lower cost is excellent value.  End of story.</p>
<p>But the implications of the story are not  just confined to the auto industry.  Cameras, computers, appliances, power tools, earthmoving equipment, and more have fallen from America&#8217;s basic manufacturing industries to a legacy of plant closings, job losses and dwindling revenues and profits.</p>
<p>Deming&#8217;s re-write of his first book on competitiveness was called &#8220;Out of the Crisis&#8221;.  What crisis one may ask?</p>
<p>This one.</p>
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		<title>Some Core Principles</title>
		<link>http://jsdstat.com/Statblog/2008/10/31/some-core-principles/</link>
		<comments>http://jsdstat.com/Statblog/2008/10/31/some-core-principles/#comments</comments>
		<pubDate>Sat, 01 Nov 2008 04:01:20 +0000</pubDate>
		<dc:creator>John</dc:creator>
		
		<category><![CDATA[Deming]]></category>

		<category><![CDATA[General Management]]></category>

		<category><![CDATA[Statistical Thinking]]></category>

		<guid isPermaLink="false">http://jsdstat.com/Statblog/2008/10/31/some-core-principles/</guid>
		<description><![CDATA[I was recently looking through some old material I had prepared for a training session with some company executives and saw this.  I think it still holds up and represents a good index of Deming key principles&#8230;it is not complete, I don&#8217;t think, but paying attention to these things in the right way will [...]]]></description>
			<content:encoded><![CDATA[<p>I was recently looking through some old material I had prepared for a training session with some company executives and saw this.  I think it still holds up and represents a good index of Deming key principles&#8230;it is not complete, I don&#8217;t think, but paying attention to these things in the right way will certainly lead to world-class competitiveness.</p>
<p><span id="more-132"></span></p>
<p>Each category could have several points made about it and, as time allows, I&#8217;ll go into some detail on each of them in the coming days and weeks.</p>
<p>•	Quality as Competitive Strategy- The Chain Reaction</p>
<p>•	Market Surveys - Living with the Customer</p>
<p>•	Quality equals continuous improvement - Not just meeting requirements</p>
<p>•	Statistical/Scientific Thinking - Vital to improvement</p>
<p>•	Top Management Responsiblity - &#8220;Quality starts in the Board Room!&#8221;</p>
<p>•	Knowledge as the basis</p>
<p>•	Not &#8216;Instant Pudding</p>
<p><strong>Deming&#8217;s System of Profound Knowledge</strong></p>
<p>•	Theory of Systems</p>
<p>•	Theory of Variation</p>
<p>•	Theory of Knowledge</p>
<p>•	Theory of Psychology</p>
<p><strong>AND</strong></p>
<p>*	The Interactions therefrom</p>
<p><strong>Deming&#8217;s Psycho-Social Focus</strong></p>
<p>•	Joy in Work - There is a birthright to joy in work.</p>
<p>•	Beat down the Societal Forces of Destruction</p>
<p>•	Win/Win - Do away with win/lose competition</p>
<p>*	Need any Country be Poor - Management and Poverty</p>
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		<title>On the Economy</title>
		<link>http://jsdstat.com/Statblog/2008/10/06/on-the-economy/</link>
		<comments>http://jsdstat.com/Statblog/2008/10/06/on-the-economy/#comments</comments>
		<pubDate>Tue, 07 Oct 2008 05:03:06 +0000</pubDate>
		<dc:creator>John</dc:creator>
		
		<category><![CDATA[Statistical Thinking]]></category>

		<guid isPermaLink="false">http://jsdstat.com/Statblog/2008/10/06/on-the-economy/</guid>
		<description><![CDATA[The Gods of the Copybook Headings
AS I PASS through my incarnations in every age and race,
I make my proper prostrations to the Gods of the Market Place.
Peering through reverent fingers I watch them flourish and fall,
And the Gods of the Copybook Headings, I notice, outlast them all.

We were living in trees when they met us. [...]]]></description>
			<content:encoded><![CDATA[<p>The Gods of the Copybook Headings</p>
<p>AS I PASS through my incarnations in every age and race,<br />
I make my proper prostrations to the Gods of the Market Place.<br />
Peering through reverent fingers I watch them flourish and fall,<br />
And the Gods of the Copybook Headings, I notice, outlast them all.</p>
<p><span id="more-131"></span></p>
<p>We were living in trees when they met us. They showed us each in turn<br />
That Water would certainly wet us, as Fire would certainly burn:<br />
But we found them lacking in Uplift, Vision and Breadth of Mind,<br />
So we left them to teach the Gorillas while we followed the March of Mankind.</p>
<p>We moved as the Spirit listed. They never altered their pace,<br />
Being neither cloud nor wind-borne like the Gods of the Market Place,<br />
But they always caught up with our progress, and presently word would come<br />
That a tribe had been wiped off its icefield, or the lights had gone out in Rome.</p>
<p>With the Hopes that our World is built on they were utterly out of touch,<br />
They denied that the Moon was Stilton; they denied she was even Dutch;<br />
They denied that Wishes were Horses; they denied that a Pig had Wings;<br />
So we worshipped the Gods of the Market Who promised these beautiful things.</p>
<p>When the Cambrian measures were forming, They promised perpetual peace.<br />
They swore, if we gave them our weapons, that the wars of the tribes would cease.<br />
But when we disarmed They sold us and delivered us bound to our foe,<br />
And the Gods of the Copybook Headings said: &#8220;Stick to the Devil you know.&#8221;</p>
<p>On the first Feminian Sandstones we were promised the Fuller Life<br />
(Which started by loving our neighbour and ended by loving his wife)<br />
Till our women had no more children and the men lost reason and faith,<br />
And the Gods of the Copybook Headings said: &#8220;The Wages of Sin is Death.&#8221;</p>
<p>In the Carboniferous Epoch we were promised abundance for all,<br />
By robbing selected Peter to pay for collective Paul;<br />
But, though we had plenty of money, there was nothing our money could buy,<br />
And the Gods of the Copybook Headings said: &#8220;If you don&#8217;t work you die.&#8221;</p>
<p>Then the Gods of the Market tumbled, and their smooth-tongued wizards withdrew<br />
And the hearts of the meanest were humbled and began to believe it was true<br />
That All is not Gold that Glitters, and Two and Two make Four<br />
And the Gods of the Copybook Headings limped up to explain it once more.</p>
<p>As it will be in the future, it was at the birth of Man<br />
There are only four things certain since Social Progress began.<br />
That the Dog returns to his Vomit and the Sow returns to her Mire,<br />
And the burnt Fool&#8217;s bandaged finger goes wabbling back to the Fire;</p>
<p>And that after this is accomplished, and the brave new world begins<br />
When all men are paid for existing and no man must pay for his sins,<br />
As surely as Water will wet us, as surely as Fire will bum,<br />
The Gods of the Copybook Headings with terror and slaughter return!</p>
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		<title>Sporadic postings&#8230;</title>
		<link>http://jsdstat.com/Statblog/2008/09/18/sporadic-postings/</link>
		<comments>http://jsdstat.com/Statblog/2008/09/18/sporadic-postings/#comments</comments>
		<pubDate>Fri, 19 Sep 2008 06:48:00 +0000</pubDate>
		<dc:creator>John</dc:creator>
		
		<category><![CDATA[Statistical Thinking]]></category>

		<guid isPermaLink="false">http://jsdstat.com/Statblog/2008/09/18/sporadic-postings/</guid>
		<description><![CDATA[My apologies for the sporadic nature of the postings here.  I have been occupied elsewhere for a few weeks and will be for a few weeks more, so in about a month, some regular posting will begin again.  In the meantime, I will post as I find the time.

  addthis_url    = [...]]]></description>
			<content:encoded><![CDATA[<p>My apologies for the sporadic nature of the postings here.  I have been occupied elsewhere for a few weeks and will be for a few weeks more, so in about a month, some regular posting will begin again.  In the meantime, I will post as I find the time.</p>
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		<title>Interactions and Systems</title>
		<link>http://jsdstat.com/Statblog/2008/07/26/interactions-and-systems/</link>
		<comments>http://jsdstat.com/Statblog/2008/07/26/interactions-and-systems/#comments</comments>
		<pubDate>Sat, 26 Jul 2008 16:08:57 +0000</pubDate>
		<dc:creator>John</dc:creator>
		
		<category><![CDATA[Deming]]></category>

		<category><![CDATA[General Management]]></category>

		<category><![CDATA[Statistical Thinking]]></category>

		<category><![CDATA[competitive challenge]]></category>

		<category><![CDATA[interactions]]></category>

		<category><![CDATA[systems thinking]]></category>

		<guid isPermaLink="false">http://jsdstat.com/Statblog/2008/07/26/interactions-and-systems/</guid>
		<description><![CDATA[This discussion goes to the heart of a subject which we don’t discuss nearly enough and that is interactions.

In a predictive model there are typically what statisticians call ‘main effects’.  A good example in medicine is the effect of particular medications.  But sometimes medications in combination potentiate (or neutralize) each other.  In [...]]]></description>
			<content:encoded><![CDATA[<p>This discussion goes to the heart of a subject which we don’t discuss nearly enough and that is interactions.</p>
<p><span id="more-128"></span></p>
<p>In a predictive model there are typically what statisticians call ‘main effects’.  A good example in medicine is the effect of particular medications.  But sometimes medications in combination potentiate (or neutralize) each other.  In other words there is another effect caused by the combination of medicines that changes the outcome.  That is the idea of an interaction.  A catalyst in a chemical reaction might be another example.</p>
<p>One of the aspects of systems is that the parts of them interact.  So it is with SOPK.  Each of the pillars interacts with the others to produce effects that none produces alone.  Marc Hersch’s continuing references to reductionist thinking is getting at this point.  The “System of Profound Elephants” is a metaphor for the fact that one cannot understand an elephant to be a collection of components.</p>
<p>Consider a pile of sand.  With a shovel you can divide it in two and have two smaller piles of sand.  Cutting a cow in two does not produce two small cows.</p>
<p>Consider  an example Deming loved to use; that of the symphony orchestra.   An orchestra is not a collection of soloists.   Two orchestras can play the same piece with the composition of the orchestra being the same and every note played being identically, but what a difference there can be.  It’s how they play together that makes a difference.  That is, it’s the sound of the individual and the interaction of the components that creates the sound.</p>
<p>On a more mundane level we can have team working on a task.  A new member is added and suddenly the team’s progress accelerates markedly.  A positive interaction at work.  Or a different team after adding a person suddenly grinds to a halt.  It’s how the team (a system) works together.  The first instance we call “Good chemistry”.</p>
<p>Successful managers understand these interactions, how they work and they manage them as well as the main effects.</p>
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		<title>Hypothesis Testing III - The statistics</title>
		<link>http://jsdstat.com/Statblog/2008/07/20/hypothesis-testing-iii-the-statistics/</link>
		<comments>http://jsdstat.com/Statblog/2008/07/20/hypothesis-testing-iii-the-statistics/#comments</comments>
		<pubDate>Sun, 20 Jul 2008 21:07:27 +0000</pubDate>
		<dc:creator>John</dc:creator>
		
		<category><![CDATA[Research Methods]]></category>

		<category><![CDATA[Scientific Thinking]]></category>

		<category><![CDATA[Statistical Thinking]]></category>

		<category><![CDATA[]]></category>

		<category><![CDATA[Deming]]></category>

		<category><![CDATA[hypothesis testing]]></category>

		<category><![CDATA[Six Sigma]]></category>

		<category><![CDATA[SPC]]></category>

		<category><![CDATA[statistical methods]]></category>

		<guid isPermaLink="false">http://jsdstat.com/Statblog/2008/07/20/hypothesis-testing-iii-the-statistics/</guid>
		<description><![CDATA[To continue, we need to define a couple of terms.  The first is a probability density function and the second is a sampling distribution.A probability density function expresses a particular function in terms of integrals.  Thus for a frequency distribution smoothed (over repeated sampling) to form a curve as shown below, the area [...]]]></description>
			<content:encoded><![CDATA[<p>To continue, we need to define a couple of terms.  The first is a probability density function and the second is a sampling distribution.A probability density function expresses a particular function in terms of integrals.  Thus for a frequency distribution smoothed (over repeated sampling) to form a curve as shown below, the area under the curve can be calculated and the probability of a given value occurring in the distribution can be assessed as a proportion of the amount of the curve that is to the left and/or to the right of the value.  In a normal distribution, z values are used to do this.<img src="http://www.jsdstat.com/Statblog/wp-images/Normal%20Model.jpg" alt="Normal Curve" /></p>
<p><span id="more-127"></span></p>
<p>Using that model we can see that in a Normal Distribution approximately 31.73 of the values fall between plus and minus one standard deviation from the mean (average).  So, for example, if the average height of a group of school boys is 155cm and the standard deviation is 5cm, we would expect a little over 68% of the boys to fall between 150cm and 160cm if height is normally distributed.  We can go a bit further and say, if height is Normally distributed, the chances of beingOn the horizontal axis is the measure of interest (if we were studying height of kids it might be height in centimeters).  In this depiction the average of the measurements is set to zero and the spread is measured  as plus or minus one, two and three standard deviations. The vertical axis represents the frequency of occurrence of a particular point on the curve.  The highest point, the average, is the one that occurs most often and as one moves away from the average, the frequency of occurrence decreases.  Because this is a theoretical model, the tails (the extreme left or right points) are asymptotic; that is, they don’t touch.  This is an important distinction between theoretical curves (such as the Gaussian or Normal Distribution) and the real world.Each statistic used to test hypotheses has a probability distribution associated with it.</p>
<p>It is from that distribution that probability distribution that we make our decision as to the sufficiency of evidence of an experimental effect.Recall that we originally formed two hypotheses, the research hypothesis (what we think the effect will be of our action) and the null hypothesis which states that there is no effect at all.  We likened the hypothesis testing logic to that of the court room where the burden of proof  rests with the person (organization) making the assertion of an effect  That is, enough evidence of an effect (guilt) must be presented to cause us to reject the “no effect” starting assumption.The hypothesis is tested in a study or experiment and a numerical estimate of an effect is produced.  For example if two suppliers are to be compared as to the relative quality of their products, a sample from each supplier might be obtained.  The samples are measured and an average value calculated for the sample from each supplier.  The null hypothesis might be that there is no difference between the two suppliers.  The means are compared and a difference is calculated and a test statistic (in this case “t”) is generated.</p>
<p>There is, as we said, a sampling distribution for the statistic t.  A probability distribution has been created showing the frequency of occurrence for different values of ‘t’ that would be obtained when repeated samples have been drawn from the same population.  That is, when the null hypothesis is true.  This is important.  Our value for t is compared with values for t obtained when the samples are drawn from the same pool.  That is, we know they are not from different samples; the null hypothesis is true by definition.There are as we said, two mistakes that can be made.  We can say that the two suppliers are different when they really aren’t or we can fail to say they are different when they are.</p>
<p>We can set the probability of making the first type of mistake as the cut off point at which we will decide there is sufficient evidence to assume there is some experimental effect.Thus if we have a t value that has less than a 1% of occurring when the null hypothesis is true, we will say that this occurrence is unlikely and we’ll reject the hypothesis as being very unlikely.  How unlikely?  We’d expect a difference this large (or larger) less than 1 time in 100 occurrences.</p>
<p>Does that mean that the alternative hypothesis is correct?  Not at all.  It means that according to the criteria we set for evidence we have rejected the idea that the difference between the two means is due to chance.  We could be wrong…in fact if we do enough of these types of comparisons, we will be wrong.Are we wrong in this case?  If we had enough information to answer that question, we wouldn’t need to do the test.</p>
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		<title>Hypothesis Testing II - The logic</title>
		<link>http://jsdstat.com/Statblog/2008/07/07/hypothesis-testing-ii-the-logic/</link>
		<comments>http://jsdstat.com/Statblog/2008/07/07/hypothesis-testing-ii-the-logic/#comments</comments>
		<pubDate>Mon, 07 Jul 2008 18:09:07 +0000</pubDate>
		<dc:creator>John</dc:creator>
		
		<category><![CDATA[General Management]]></category>

		<category><![CDATA[Research Methods]]></category>

		<category><![CDATA[Scientific Thinking]]></category>

		<category><![CDATA[Statistical Thinking]]></category>

		<guid isPermaLink="false">http://jsdstat.com/Statblog/2008/07/07/hypothesis-testing-ii-the-logic/</guid>
		<description><![CDATA[A hypothesis is a supposition made as a basis for research or reasoning without regard for its truth.  So says the Oxford dictionary.  What starts the hypothesis testing process is just such a supposition.  In the justice system example we made, there is a supposition on the part of law enforcement that [...]]]></description>
			<content:encoded><![CDATA[<p>A hypothesis is a supposition made as a basis for research or reasoning without regard for its truth.  So says the Oxford dictionary.  What starts the hypothesis testing process is just such a supposition.  In the justice system example we made, there is a supposition on the part of law enforcement that the apprehended person committed the crime.In pharmaceutical testing, there may be a supposition a given medicine will reduce cholesterol values in blood tests.Because of the nature of induction we can never prove theory going forward.  As a prediction we recognize that the samples of interest are not those of the past, but rather those of the future and they have not happened yet.  Thus they are not available to be sampled for our study and they may, in some way, be different from the samples that are available for the study.Further, that difference could render the results that are (necessarily) based on the samples in the study inapplicable to the future samples.  This problem is unavoidable.  So we design a way to test our hypothesis in another way.  One aspect will be that the statements we can make will be probabilistic.  We are in the land of uncertainty.To do our test we create another hypothesis called the null hypothesis.  The Null hypothesis is essentially an assumption that the research supposition (Research Hypothesis) has no merit.  In our justice system case, it is an assumption of innocence.  In the pharmaceutical case the null hypothesis would state that the new drug had no effect on lowering cholesterol.So there are two hypotheses.  The null hypothesis (usually designated H0  and the research hypothesis which is usually, and somewhat unfortunately, called the alternate hypothesis (usually designated H1 or HA).  I say unfortunately because this is the hypothesis that we are most interested in and the word ‘alternate’ makes it seem almost secondary.Thus the comparison is constructed in such a way as to pose the null hypothesis and the burden of rejecting that (no difference) hypothesis rests with the advocate of the alternate hypothesis.  That is, if the research can provide enough evidence to reject the null hypothesis, there is reason to believe that the new drug does have an affect on cholesterol.  If the prosecutor can provide enough evidence we will suggest that the apprehended person did commit the crime.We could be wrong.  People sometimes ask a statistician to give a yes or no answer or to provide certain proof.  That simply cannot be done and that is a problem fundamental to the inductive nature of this process.  It is for this reason that we do not accept the alternate hypothesis in the sense that it is ‘proven’.  The logic of hypothesis testing this way leads to either reject the null (no difference) hypothesis or to not reject it.A standard of proof is given. In the justice example in the United States that standard is that the proof must be ‘beyond a reasonable doubt’.  In a research study, such as the pharmaceutical example, we set probability level (more about this later).If that standard is met or exceeded we reject the null hypothesis.  If the standard is not met we do not reject it.</p>
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		<title>Quality, Productivity and Competitive Position</title>
		<link>http://jsdstat.com/Statblog/2008/07/04/quality-productivity-and-competitive-position/</link>
		<comments>http://jsdstat.com/Statblog/2008/07/04/quality-productivity-and-competitive-position/#comments</comments>
		<pubDate>Fri, 04 Jul 2008 20:44:06 +0000</pubDate>
		<dc:creator>John</dc:creator>
		
		<category><![CDATA[Deming]]></category>

		<category><![CDATA[General Management]]></category>

		<category><![CDATA[Statistical Thinking]]></category>

		<category><![CDATA[]]></category>

		<category><![CDATA[competitive position]]></category>

		<category><![CDATA[competitiveness]]></category>

		<guid isPermaLink="false">http://jsdstat.com/Statblog/2008/07/04/quality-productivity-and-competitive-position/</guid>
		<description><![CDATA[June marked the 25th anniversary of the publication of Dr. W. E. Deming’s first management book, “On Quality, Productivity and Competitive Position”.  Deming lived both in Washington D. C. and New York where he kept an apartment on Hudson St. in the Village. He was a professor at NYU’s Graduate School of Business Administration [...]]]></description>
			<content:encoded><![CDATA[<p>June marked the 25th anniversary of the publication of Dr. W. E. Deming’s first management book, “On Quality, Productivity and Competitive Position”.  Deming lived both in Washington D. C. and New York where he kept an apartment on Hudson St. in the Village. He was a professor at NYU’s Graduate School of Business Administration from 1946 until his death in 1993.   He also taught for years at Columbia. While returning to his apartment one evening in 1968 he was mugged and stabbed and was rushed to St. Vincent’s Hospital where he spent several days; a true New Yorker, indeed.Deming was born in 1900 in Iowa and spent the bulk of his early childhood in Polk City and then at around age 7 moved to Cody, Wyoming and later Powell, Wyoming.  Life was harsh and he lived, as did many, in a tarpaper shack.  He would joke in his seminars that he would wager he was the only person in the room that was born in the reign of Queen Victoria.For those unfamiliar with Deming (which seems to include much of corporate America) he is perhaps best known for his trips to Japan after the end of World War II.  He had traveled to Japan in 1947 originally to help occupation forces to conduct sampling research for a census.His visit was not unnoticed by the fledgling Union of Japanese Scientists and Engineers (JUSE) and he was invited to return to Japan at a later date to conduct a series of classes on the statistical quality control techniques that had proved so beneficial to the United States in the production of high quality materials for defense manufacturers.He did return in 1950 and conduct those classes.  They were primarily in the area of what, at that time, was called Statistical Quality Control.  But Deming also taught another course.  The essence of this teaching is captured in the speech he gave to many of the top managers of Japanese post-war management at Mt. Hakone in 1950.At that meeting Deming outlined a competitive strategy that has come to be known as the “Deming Chain Reaction”.  Basically it is simple in concept, but difficult in execution.It had always been thought that better quality could only be achieved at higher cost.  That is, there is a theoretical point at which further attempts to improve quality would inflate price so much that the object being manufactured is no longer marketable because of its cost.  As it turns out, that is only true if attempts to improve quality are focused on inspection.  When one focuses attention on quality through process improvement and the elimination of waste, quality improves and costs go down at the same time.There is no better example of this strategy at work than Toyota Motors.  But there are many, many other examples as well.  We, in America, are all too familiar with the phenomenon of products invented and developed here that are manufactured elsewhere.  The result has been a huge deindustrialization of America.  Industrial America today is half the size it was 30 years ago.  The effect of this deindustrialization on the economy has been devastating.Deming predicted Japan’s success in the 50s when no one else was paying attention to them economically at all.  He foresaw the de-industrialization of America and entitled his next book, “Out of the Crisis”.  Both books contain the basics of his ideas about how to be competitive.  Perhaps for  America he was too far ahead of his time.In keeping with his upbringing Deming worked right up until his death in 1993.  He maintained his active consultancy and taught his famous “4-Day” seminar until a few weeks before the end.  He was tough.I had the good fortune to know him personally and he was a wonderfully kind and gracious man as well.  I can still clearly hear his words,  “There is no substitute for knowledge.”  The knowledge is there in the pages of his book.  It needs only to be extracted and acted on.</p>
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		<title>Tests of Hypothesis</title>
		<link>http://jsdstat.com/Statblog/2008/07/03/tests-of-hypothesis/</link>
		<comments>http://jsdstat.com/Statblog/2008/07/03/tests-of-hypothesis/#comments</comments>
		<pubDate>Thu, 03 Jul 2008 16:37:07 +0000</pubDate>
		<dc:creator>John</dc:creator>
		
		<category><![CDATA[General Management]]></category>

		<category><![CDATA[Research Methods]]></category>

		<category><![CDATA[Scientific Thinking]]></category>

		<category><![CDATA[Statistical Thinking]]></category>

		<category><![CDATA[research]]></category>

		<category><![CDATA[Six Sigma]]></category>

		<category><![CDATA[statistical theory]]></category>

		<category><![CDATA[statistics]]></category>

		<guid isPermaLink="false">http://jsdstat.com/Statblog/2008/07/03/tests-of-hypothesis/</guid>
		<description><![CDATA[When discussing hypothesis testing, I have, from time to time, used the example of the criminal justice system to act as a metaphor for the logic and philosophical issues involved.  It remains a good way to pose the logical dilemmas and the types of errors involved and to also discuss the idea of a [...]]]></description>
			<content:encoded><![CDATA[<p>When discussing hypothesis testing, I have, from time to time, used the example of the criminal justice system to act as a metaphor for the logic and philosophical issues involved.  It remains a good way to pose the logical dilemmas and the types of errors involved and to also discuss the idea of a system generally and how to improve it.There is, in the American system of justice, a presumption of innocence.  That is, the burden of proof that a crime was committed rests with the government (the prosecutor).  In a research situation, the burden of proof rests with the advocate of the research hypothesis (e.g. a researcher may assert that this drug will work to cure this disease)Using our criminal justice example, a first hypothesis (in statistics usually called a null (no difference) hypothesis) would state that the person who has been apprehended is innocent.  This hypothesis can only be rejected if sufficient evidence of guilt is produced.  In the research example, the null hypothesis (as it is called) would be that the drug does not work to cure the disease.The second (alternate) hypothesis is that the individual is guilty.  The government takes this position, that’s why they arrested the individual.  The question is can the prosecutor produce enough evidence of guilt to establish guilt.  The burden, as we have said, rests with the prosecutor.  In the drug example, the second hypothesis is sometimes called the research hypothesis and in our drug case, it would be that the drug does cure the disease.There are two mistakes we can make.  We can let a guilty person go free.  Or, alternatively we can call a person guilty who is, in fact, innocent.  Or, we can say the drug works when it doesn’t, or we can fail to detect that the drug does work and conclude that it doesn’t.Usually in statistics those are called Type I and Type II errors.  Or, ‘Errors of the First Kind and Errors of the Second Kind.  To be clear, Errors of the First Kind are to mistakenly reject the no difference (null) hypothesis.  Errors of the Second Kind would be to failing to reject the no difference hypothesis when there was actually a difference (the person is guilty)So, in the criminal justice case, we have a trial.  In the research case, we do a research study.The innocence or guilt of the person at trial is not known.  We do not know for certain if the drug works.  That is the key.  If we knew for certain, we wouldn’t need a trial.And because of that uncertainty we will make those mistakes.Statistics has been called a tool for “…making decisions in the light of uncertainty…” If we had a sure fire way to know the innocence or guilt of the individual, we wouldn’t need the trial or study.  But we are uncertain.So we set a standard of proof.  A pre-selected point or criterion that, when met, will be sufficient to say we will make a decide this way or that.   In the U. S. criminal justice system, that standard is ‘…beyond a reasonable doubt’.   In other words, the null hypothesis (the presumption of innocence) has to be rejected beyond a reasonable doubt.It is important to realize that this standard is arbitrary.  There is nothing about it derived from theory that makes one standard more valid than another.  Obviously the selection of the standard will affect the frequency with which one makes the two mistakes.It is popular to try to avoid making the two mistakes.   Cries of outrage are heard whenever a person thought to be guilty is freed and we find (particularly since the advent of DNA testing) that non-guilty people are sometimes convicted in spite of their evident innocence.It may be no consolation to the victims in these cases, but from a system point of view it is important to understand that these mistakes are inevitable.  They are a function of the uncertainty.  Only in the most extreme circumstances can either of these mistakes be eliminated and that is by committing the other mistake as often as possible.If society never wants to convict an innocent person, don’t convict anyone.  But the maximum number of guilty people will go un-convicted.  If society never wants to let a guilty person go free, then convict everyone.  But the maximum number of innocent people will be convicted.Outside of those extreme cases, the mistakes are unavoidable.  They each will be committed; one once in a while and the other once in a while.Thus the aim of any study framework should be to try to achieve a balance.One more note before moving on.  If we fail to reject the no difference hypothesis, it does not necessarily follow that the alternate hypothesis is true.  Just because we don’t convict the individual in court does not mean that he or she is innocent.  It means that we could not meet the burden of proof.  Because the standards are arbitrary they can be set in such a way as to make meeting the burden of proof easier or more difficult.Part II – How it works in statistics</p>
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		<title>Six Sigma III</title>
		<link>http://jsdstat.com/Statblog/2008/06/29/six-sigma-iii/</link>
		<comments>http://jsdstat.com/Statblog/2008/06/29/six-sigma-iii/#comments</comments>
		<pubDate>Sun, 29 Jun 2008 20:21:11 +0000</pubDate>
		<dc:creator>John</dc:creator>
		
		<category><![CDATA[Deming]]></category>

		<category><![CDATA[General Management]]></category>

		<category><![CDATA[Statistical Thinking]]></category>

		<category><![CDATA[competitiveness]]></category>

		<category><![CDATA[continuous improvement]]></category>

		<category><![CDATA[quality]]></category>

		<category><![CDATA[quality improvement]]></category>

		<category><![CDATA[Six Sigma]]></category>

		<guid isPermaLink="false">http://jsdstat.com/Statblog/2008/06/29/six-sigma-iii/</guid>
		<description><![CDATA[Imagine you are an executive in an organization that defines quality as absence of defects.  How, then, would you plan to improve quality?It’s obvious isn’t it?  Spend time being clear about what are defects and what are not (via specifications), find points to check for defects and, if they are found, remove them. [...]]]></description>
			<content:encoded><![CDATA[<p>Imagine you are an executive in an organization that defines quality as absence of defects.  How, then, would you plan to improve quality?It’s obvious isn’t it?  Spend time being clear about what are defects and what are not (via specifications), find points to check for defects and, if they are found, remove them.  Institute a corrective action process attempting to avoid recurrence of the defect.Now, put a different hat on your head.  You are an executive in an organization that defines quality as continuous improvement.  What do you do to assure quality?Define quality in terms of the customer (the only eyes that matter) would be the first step.  Second would be to analyze processes in the organization to see to what extent they achieve the quality definition.  Then, begin a continuing effort to reduce variation and center processes on target.Note that the approaches are fundamentally different in emphasis.  Naturally, activities overlap and both kinds efforts involve teamwork, training, coordination and leadership.  But the focus is different.Now, reconsider the competitive track record of organizations that define quality as a never ending process of continuing improvement and the competitive track record of those companies that chase defects.There really is no comparison.  Those companies adopting the continuous improvement paradigm (e.g. Toyota, Honda, Canon) have maintained high levels of quality, lower or comparable costs and better values over the years and their profitability shows it.The Six Sigma approach is chasing defects.  Finding and correcting problems is not improving quality, it is merely getting process to operate the way they were originally intended to run.  Zero defects is not good enough in today&#8217;s competitive world.  Not when you are competing with someone that does not  stop trying to improve once the defects are gone.To repeat:  It’s all fairly simple really.  Pay attention to quality in the right way and quality improves while costs go down.  Enter the market with better quality at lower cost and capture the market.There is no longer the slightest doubt that this method is the key to competitive excellence.</p>
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