It's hard to get perspective sometimes on the differences between Clinton and Obama in the delegate counts. For me at least, numbers and text just don't do it. I'm more of a visual person. Here is a graph showing the pledged delegate lead from day 1. Each point represents a different day where an election has been held. It helps me to see the history of the lead as well as the projected future.
Day 1 is Iowa, day 5 is Super Tuesday, day 11 is Wyoming, etc. What is plotted is the net pledged delegate lead by Obama (he's currently up 154 according to the Obama website).
The black line is what has already transpired using the data on Obama's results page. The blue line is from the projections on the leaked spreadsheet after super Tuesday. I like seeing a range of results, so there are 2 other scenarios shown. The red line shows what happens if Clinton wins 55% of pledged delegates in every contest here on out. Very unlikely of course, but it shows a worst case. Obama has typically beaten the spreadsheet projections, so the green line shows what happens if he keeps beating the projections by the average amount he has so far (an extra 3 delegates per contest).
Presented this way the data also point to some interesting conclusions. Contrary to the narrative that it is caucuses that have given Obama his lead, the 2 biggest jumps so far have been the combined effect of Washington and Louisiana on day 6 (Feb 12) and the Potomac primaries on day 8. Other than that they are running about even, with Obama getting smaller jumps in a couple of places.
Now I get the feeling that a lot of Clinton supporters have given up on the pledged delegate count and have pointed at the popular vote totals as being more representative. So here's the popular vote graph. Note that I used the totals from CNN. This gives Clinton the advantage since caucuses add relatively few votes to the CNN popular vote total. For example, Washington gave Obama a 10,000 popular vote margin in the caucuses, but a 40,000 vote margin in the primary that didn't count. In the popular vote numbers race, caucuses are at a disadvantage.
I did similar projections as before. The blue line is from the spreadsheet, the red line is from Clinton winning by 5% in every contest, and the green line is from the spreadsheet plus the average amount by which it underestimated his wins. In the last 8 primaries the spreadsheet underestimated by an average of 8%, but last Tuesday the spreadsheet only underestimated by an average of 1% (yes, he did better on Tuesday then he predicted). I settled on a 4% undershoot margin to balance his overall trend with Clinton's latest momentum. I didn't include his winning margin in caucuses in the estimate since the remaining contests are all primaries (might as well compare apples to apples).
I also had to predict turnout to complete the projections. Looking at a range of small, big, red, blue, etc. states, the turnout so far has been in the range of 10%-20% of the state population, so I used 15%. I played with the percentage to see how sensitive the lines were to the number, and it didn't change the qualitative nature of the trends.
Here you see the biggest jump was the Potomac primary, with the Washington/Louisiana contest having a smaller effect on the popular vote total. If it weren't for MD, VA, and DC, they'd be about equal. It's not the caucuses that have been keeping Obama ahead. If he wins, Obama needs to thank the DC area for their support.
In conclusion, my impression of the race is one in which a football analogy is appropriate. Obama scored big in the 2nd quarter with a couple of touchdowns. The rest of the time they've been trading fieldgoals. Last Tuesday, Clinton had a couple of spectacular long catches, but couldn't score in the red zone and only got a couple of field goals. The 3rd quarter is about to end with Mississippi, and it's looking like fieldgoals here on out.
I hope the graphs give people some better perspectives on the race so far. I'm working on adding superdelegates and FL&MI into the data, but I have to get back to yardwork now. ;-) We only get so many sunny days in Seattle.