Share via Share via... Twitter LinkedIn Facebook Pinterest Telegram WhatsApp Yammer RedditRecent ChangesSend via e-MailPrintPermalink × This is an old revision of the document! Cross sectional studies Cross sectional studies ut, video /* Number 4 5 */ unit of analysis variable attribute variable value causality spurious relationship time order reverse causation dependent variable endogenous concept independent variable exogenous concept cross-sectional research external invalidity internal invalidity ut video