A computer-implemented method for generating a trustworthiness index, comprising: under the control of one or more computer systems configured with executable instructions, determining a scan level of a first set of sites based on parameters associated with the first set of sites; measuring one or more security factor values, each security factor value associated with a security factor of a set of security factors, the one or more security factor values measured based at least in part on a set of security scans of the first set of sites at the scan level, the set of security scans comprising a plurality of security scans, the set of security scans performed over a non-zero time span; generating, for one or more sites of the first set of sites, a first set of security indices associated with one or more of the set of security factors, each security index of the first set of security indices based at least in part on the one or more security factor values; calculating one or more normalized security indices associated with the first set of security indices by at least: a) retrieving, from a data store, a second set of security indices, each security index of the second set of security indices associated with a site of a second set of sites, the second set of sites at least including one or more sites differing from one or more of the first set of sites; and b) normalizing one or more of the first set of security indices to produce the one or more normalized security indices based at least in part on one or more of the second set of security indices; providing the one or more of the one or more normalized security indices to the data store; and providing, to the data store, a trustworthiness index associated with one or more associated sites of the first set of sites, the trustworthiness index based at least in part on combining one or more of the one or more normalized security indices. determining a scan level of a first set of sites based on parameters associated with the first set of sites; measuring one or more security factor values, each security factor value associated with a security factor of a set of security factors, the one or more security factor values measured based at least in part on a set of security scans of the first set of sites at the scan level, the set of security scans comprising a plurality of security scans, the set of security scans performed over a non-zero time span; generating, for one or more sites of the first set of sites, a first set of security indices associated with one or more of the set of security factors, each security index of the first set of security indices based at least in part on the one or more security factor values; calculating one or more normalized security indices associated with the first set of security indices by at least: a) retrieving, from a data store, a second set of security indices, each security index of the second set of security indices associated with a site of a second set of sites, the second set of sites at least including one or more sites differing from one or more of the first set of sites; and b) normalizing one or more of the first set of security indices to produce the one or more normalized security indices based at least in part on one or more of the second set of security indices; a) retrieving, from a data store, a second set of security indices, each security index of the second set of security indices associated with a site of a second set of sites, the second set of sites at least including one or more sites differing from one or more of the first set of sites; and b) normalizing one or more of the first set of security indices to produce the one or more normalized security indices based at least in part on one or more of the second set of security indices; providing the one or more of the one or more normalized security indices to the data store; and providing, to the data store, a trustworthiness index associated with one or more associated sites of the first set of sites, the trustworthiness index based at least in part on combining one or more of the one or more normalized security indices.