Take the example of rape measurement: better statistical and reporting methods used by the police, combined with less social stigma and other factors result in statistics showing a rising number of rapes, but this increase is due to the measurement methods and other effects, not to what happened in real life. The actual number of rapes may have gone down.
This is a general problem in human rights measurement: more often means less, and vice versa. The nature of the thing we’re trying to measure – human rights violations – means that the more there is, the more difficult it is to measure; and the more difficult, the more likely that we wrongly conclude that there is less. (See here). When levels of rights violations approach totalitarianism, people won’t report, won’t dare to speak, or won’t be able to speak. It’s not social stigma or shame that prevents them from speaking, as in the case of rape, but fear. Furthermore, totalitarian governments won’t allow monitoring, and will have managed to some extent to indoctrinate their citizens. Finally, the state of the economy won’t allow for easy transport and communication, given the correlation between economic underdevelopment and totalitarian government.
Conversely, higher levels of respect for human rights will yield statistics showing more rights violations, because a certain level of respect for human rights makes monitoring easier.
More on measuring human rights.