Why are daily gains and loses skewed in the major markets?

I wasn't sure where to post this, so I landed here because it is generalized.

Here, look at this example for today's NASDAQ...



The newswires all say that the NAZ closed up 66 points. But it is measured from yesterday's close at ~7032. But if it is measured from today's open, at ~7129, The NAZ closed down 31 points, at ~7098.

Why do they measure a day's performance of a stock/index from the previous close, rather than the performance of the stock/index whatever during it's single day open/close?

 

Because the price has still changed even if the change takes the form of a gap.

 

%%
Some charts do measure it from the open; i do it both ways, but close to close takes more time so i use that, mainly .I do record the open price.And thats a weak trend when it cant close above open, or above 200dma; weak up trend for QQQ also.

Cant tell you why the news does it;
they said DOW closed up 10 days[2017] in a row-my charts never had near that many bullish closes.LOL

 

I guess it's just a standard that helps visualize day-to-day performance, vs performance of individual days.

 

Take off your day trader's glasses, man! There's whole other world out there jk