What are the effects of Halloween?

It depends on what you look at as "effects". It varies. For example, commerically, Halloween ends up benefitting. 40% to 60% of all candy sold is done for Halloween, and greeting cards, costumes, regular foods (people host Halloween parties), decorations, fabrics, and so on all benefit from the holiday. Modern day, there are few religious effects anymore. But Halloween used to be very spiritual, superstious, and religious.