1. A computer-implemented method, comprising: receiving a query request including an audience specification, wherein the audience specification specifies one or more criterion for identifying audience members of an audience that accessed media content; identifying a plurality of audience member identifiers corresponding to the audience members that meet the audience specification, each of the plurality of audience member identifiers corresponding to a unique one of the audience members; for each of the identified audience member identifiers: generating a respective random number for the audience member identifier; and generating a random weight value for the identified audience member identifier based on a function of the respective random number and the audience member identifier; and obfuscating results data describing the identified audience member identifiers in a query result value responsive to the query request based on the random weight values for the identified audience member identifiers; wherein: generating, for each of the identified audience member identifiers, the respective random number for the audience member identifier comprises initializing a random number generator to a same seed value for each query request; generating a random weight value comprises: for each identified audience member identifier: sorting the audience member identifiers in an order based on the value of the audience member identifier; multiplying the audience member identifier by a random number output by the random number generator to create a product, wherein the sequence of random numbers output by the random number generator is the same for each query based on the same seed value; converting the product to a decimal number between two integers; and generating the random weight value by performing a function on the decimal number.