dr. kogan's comments? >> many of the comments that he made about how we as consumers of facebook feel about the way the data being used, we feel violated and we are certain that more is being used -- not about -- known about us or listened to or surveilled the truth is that , the entirety of facebook's data model, its ability to now about not only you as a person but also the potential cohort. that is not as a segment and facebook. it is extraordinarily powerful. far more powerful than anything that cambridge analytica might've done through this app. senator blumenthal there is no : there is no question that facebook's model is immensely powerful and unchecked right now. the challenge for us is to provide some oversight and protection. at the same time we are trying to prevent the innovation -- inhibition of innovation and freedom. i want to begin by exploring your points about terms of service. in fact in our last hearing with , mr. zuckerberg, i held up the terms of service that i believe were provided t

>> at the time that dr. kogan told me about the research he was doing, he told the company abt some of the research that was being done by the team russia. this email correspondence from the firm, for example, it referenced the work that he was doing for the russians, so initially through conversations that i had through dr. kogan, and then later through the investigative reporting, being done through the year from the guardian and others, more details have emerged.>> and dr. hirsch, the use of social media to micro-target is fairly recent, and my understanding is that micro-targeting is not, and the use of provided information to mobilize portions of electorate has a long history of political campaigns, so is the use of social media to micro-target different than what it has been done, and how it has been done in the past? >> we don't know about its effectiveness in some ways, but often looks the same, and responding to senator kennedy, just because campaign spent a lot of money on the particular ad kind doesn't

so since then we've had some rather conflicting evidence from dr. kogan himself, from christopher wylie about what data was supplied and used. indeed mr. wylie described that data obtained via the kogan act from facebook as the foundation data set of the companyhich may have collected data on up to al clearly the been ac by facebook following these revelations or allegations. do you want to clarify or amend now the evidence that you gave in february with respect to data supplied by gsr and dr. kogan? >> thank you. i'm grateful for that opportunity. look, clearly i accept that some of my answers could have been clearer, but i assure you that i did not intend to mislead you. of course the answer to this question should have been yes. there was certainly no intention to mislead the committee. that was my understanding, and it was a genuine misunderstanding. >> that's the head of the data firm that the trump campaign used in the 2016 elections now admitting what he had previously denied about where they got their data that they used for their political operat

we will now have a round of questions and answers and i will begin with dr. kogan.ould you describe the individual facebook user data for cambridge analytic at gained access to through the personality test app that you designed? kogan: we provided them 30 million people's worth of data. they had people's names, location, birthdate, gender, and then it listed a number of predicted personality traits. extroversion, agreeable this and a limited number of specific page likes. cambridge analytic that chose about 500 page likes from a list of about 150 million. it was a small pretended. in past eightony minutes clearly indicate that you question the effectiveness of the facebook user data to micro target voters in political campaigns. would you provide additional details of the legitimate scientific scrutiny described in your testimony regarding the effectiveness of using this data? kogan, going in i thought it would be a lot more shared most psychologist, when we do research we are not studying a specific person. we are studying people in general. this project we have to