Change in OI as an indicator of stockmovement

General
1

Hi,

They say increasing stock price with increase in OI means trend will continue. What is the logic behind this.If the stock is going up then those short the futures will cover their potions if they think the trend will continue which will result in decrease of OI.

2

http://tradingqna.com/4017/what-is-the-average-oi-change-on-nifty

3

my q was why it sayin that increase in oi with increase in stock price is bullish