The design of case control studies, looking at past events, generally prevents definitive conclusions.

Most large companies are self-insured, and Federal law generally prevents states from regulating these health benefit plans.

These amounts14 are not large, but competition generally prevents charging higher rates to some customers in order to fund reduced rates for others.

The heated water from the plant generally prevents the lake from freezing over during the winter.

The proposal would generally prevent the post office from disclosing a mail cover.

The rules generally prevent employers from denying health benefits to new employees because of pre-existing medical problems like cancer, asthma or heart disease.

Such laws generally prevent accused rapists from offering evidence of the complaining witness's sexual history.

And another generally prevented a cable operator from using more than 40 percent of its channels for programming produced by any affiliate.

But Army regulations generally prevent officers from interviewing their superiors.