A computer-implemented transmission scheme is provided to control client-server interchanges within a distributed communications network, such as a real time opinion research system. Interchanges include transmitting media streams between one or more clients to a server over a computer network, including the global Internet. A polling management unit sets and manages the transmission mode that includes event-driven and periodic interchanges. Periodic interchanges can be simultaneously or staggeredly transmitted to a sampling pool of active clients. A transmission mode unit implements the transmission scheme set by the polling management unit. A parameter selector establishes the transmission interval and transmission period which are used to trigger each communication interchange. A client assignor creates one or more sampling classes from the sampling pool by applying a sampling quotient that is generated by the parameter selector. A schedule editor produces a transmission schedule for the active clients. If more than one sampling class has been created, each sampling class would receive a separate transmission schedule for providing staggered transmissions at designated transmission intervals. The transmission schedule can include other data preparation and formatting instructions for compression, aggregation and packetization.