The value of information is the extent to which additional information improves an agent's decision. This depends on how likely that information is to change the agent's decision and how much of an improvement that change would be. Value of information will usually be higher the less resilient the agent's relevant credences currently are, because that will tend to mean new evidence is more likely to change the agent's credences.
Askell, Amanda (2017) The moral value of information, Effective Altruism, June 4.
Muehlhauser, Luke (2013) Review of Douglas Hubbard, How to Measure Anything, LessWrong, August 7.