Sunday, October 28, 2012

Peer and Self Assessment

In a previous post I discussed the need for peer assessment in a course the size of Coursera (83,000 students).  Daphne Koller, co-founder of Coursera, had presented some research on how the evaluation of peers closely matched the evaluation of teachers in her TED talk this summer.

Here's my contribution to this research based on a very small sample size - namely the evaluation of my latest Coursera exercise by my peers and by me.  It's a simple scoring system:  three categories of scoring, for Argument, Evidence, and Exposition, on each of which you can receive a score between 0 and 3.  In each of the three categories, my own self-evaluation and that of my peers matched identically.  I got back worthwhile feedback, that was completely appropriate, clearly stated, and right on target.  Sweet.

I thoroughly expect that massive amounts of data are being collected on everything about this course.  I'll be watching for papers assessing how this kind of evaluation works.

Evaluators are invited to provide their initials and where they are from.  Two of the students who evaluated me self-identified as being from Chile and Germany.  It's a truly international student cohort.

Wednesday, October 24, 2012

Major Pettigrew's Last Stand

What a lovely, old-fashioned story.  

Major Pettigrew is an old-fashioned retired army officer, who has recently lost his wife.  He has old-fashioned values of honour and loyalty.  He lives in an old-fashioned English village, Edgecombe St. Mary.  He belongs to an old-fashioned - a very old-fashioned - golf club, full of people with old-fashioned ideas of what Britons should look like.  They should be white, of a certain class, and follow traditional societal conventions.

Among the thatched cottages in the village lives a recently-widowed Pakistani shopkeeper.  She too lives in a world of convention and tradition; they're just different traditions and different values.

Who would have thought that a relationship would blossom between this unlikely pair?  How lovely to share with these characters the unfolding of that relationship.  It's a lovely relaxing read.

Tuesday, October 23, 2012

Coursera and Peer Evaluation

Readers of this blog know how enthusiastic I am about taking a course on world history on Coursera.  I've loved learning the history, and the experience has provoked many thoughts about the future of education (see this post).  Education is undergoing the process of disruptive innovation, and it's about to explode.

I've just discovered a TED talk by Daphne Koller, one of the founders of Coursera from TED Global this summer.  It outlines some of the motivations of the founders of Coursera and talks more about data on the efficacy of online teaching.

She quoted Thomas Friedman's article in the New York Times:
Big breakthroughs happen when what is suddenly possible meets what is desperately necessary. 
How true that is.

MOOCs (massive online open courses) in the social sciences must figure out a way to include written work as part of the course.  For a class of more 80,000 students, like The History of the World Since 1300,  what is desperately necessary - evaluation of those essays - meets what is suddenly possible - mass technology-enabled anonymous peer evaluation.

But can peer evaluation be effective and fair?  Koller showed some fascinating data on peer evaluation (which she acknowledged was based on relatively small samples).  Here's her chart of the very high correlation between peer grades and the grade a teacher would offer.

Even more surprising was the chart showing that self-evaluation correlated even more highly with the teacher grade (given some software that prohibited perfect scores).

I'm eager to see what my peers think of my first essay handed in a few days ago.  Coursera also asks students to self-evaluate their essays.  Coursera is so cleverly designed that I'm sure this data will all be collected and form the basis of future publications on the effectiveness of peer evaluation.  It is truly a new age!

Monday, October 15, 2012

Assignments in History of the World Since 1300

In the weekly letter from Professor Adelman in my Coursera history course, he reported that almost 1,800 of the almost 83,000 registrants in the course had handed in the first essay assignment.  He called that an 'impressive feat' by online education standards.  I wasn't sure what to expect.  Since registering is free and one click away, it's pretty easy to sign up and not engage at all.  Or to want to passively view the lectures, but not do any assignment work.  And then there would be people like me, who did the assignment, thought I'd submitted it correctly.  However, when I looked for the essays I was to mark, there were none.  (Only people who hand in an essay mark others' essays).  I assume this was my own operator error.  Sigh.

Since I did all the work, I thought I might as well include my assignment essay here for anyone who was interested.  The question I answered (chosen from three) was "How would you explain the causes and processes of European conquests of the Americas?"  So here it is:

As our course opens in the 14th Century, Europe is integrated into the AfroEurasian global network of trade and commerce.  Trade routes to/from Europe have ranged over the Silk Route and maritime routes through the Indian Ocean to the Far East.  The trade routes have been dominated by Arab merchants and traders and the language of commerce has been Arabic. 

Europe has had an enormous appetite for the goods produced from the East, especially China - goods like porcelain, silk and spices.  Yet less sophisticated goods from Europe don’t have a reciprocal appeal in the Far East: Europe’s balance of trade with China is in a deep deficit. 

The fall of Constantinople to the Ottomans in 1453, tightens the Muslim control of traditional trade routes.  The ‘Ottoman Blockade’ creates a strategic imperative for Europe to find an alternate route to the East.

To Europe’s good fortune, new shipping technologies and knowledge enable such an enterprise.  Tools like the compass and better ships have emerged, and increasing exploration down the West coast of Africa and Atlantic islands have built a knowledge base of trade winds and Atlantic currents which allow European adventurers to venture further and further into the Atlantic towards the Americas.

When Columbus achieves landfall in the Caribbean, he triumphantly asserts he’s found the coveted alternate path to the East (a belief he maintains to his death, even in the face of strong evidence to the contrary), but in fact he’s found something much more valuable for the Europeans. 

As the earliest conquerors in the Americas, the Spanish initiated patterns that were to be seen elsewhere. After initial settlements on Hispaniola, the Spaniards moved onto the continent.  In their conquest of the Aztecs, they made alliances with tribes, such as the Tlaxacan, who were rivals of the incumbent Aztecs.  Native interpreters often joined the invaders, often with the support of natives, such as Dona Maria who assisted Cortez. The conquest of the Axtec capital Teochtitlan may have fallen to 100,000 warriors, but only 600 of them were Spanish.

Disease did more to conquer the Aztecs than Spanish swords.  The invasion of European diseases ravaged the population as multiple epidemics took the population from well over 100M to less than 20M.   The Spanish conquerors entering Tenochtitlan found 40% of the population dead from disease.

The most important challenge facing the Americans was how to sustain their conquest of the Americas.  This was not a slash-and-grab operation to gather booty, but a co-ordinated effort to solidify the conquest and make the colonies work for them, both literally and figuratively.   The Europeans turned the Americas into an export economy.  Originally they exported agricultural products of moderate value.  But soon the economy turned on the mining of silver and the production of sugar.

Sugar transformed the European diet, but silver transformed the world economy.  The balance of trade, which had so favoured China pre-1492, had shifted by 1600 in favour of the Europeans.  85% of the world’s silver and 70% of the world’s gold was being produced in the Americas, and the Europeans controlled it.

Both silver mining and sugar plantations required large work forces.  Where possible, the Europeans used native Indian labour in their enterprises.  Notably, the Portuguese grafted onto the existing Mita labour system in South America, turning it into an indentured labour system.  But the effects of the epidemics meant that there simply weren’t enough natives left to man the mining and agribusinesses of the conquerors.  There was already an example of how to circumvent this labour shortage in the Canaries and Azores: import African slaves.  Slavery became the mainstay of the Americas.  In fact, of the 6.5M immigrants to American up to 1776, 5.5M of them were involuntary immigrants, the African slaves.  By the end of the slave trade, 10-12M Africans had been shipped to the Americas, a staggering number when you consider the relative populations of those days.  40% went to Brazil, 30% to the Caribbean and less than 5% to North America.

So the European process for solidifying their new colonies was to create an export-led economy, whose riches would line European pockets.  Labour shortages were overcome through the use of African slaves.