媒介公信力的测量结果会随着时间推移、媒介生态变化而改变。2009 年,新浪微博 上线拉开了中国社交媒体的发展序幕;2012 年,微信朋友圈上线开启了中国社交媒体的 全面发展时期。当社交媒体发展成为新的媒介单元后,最重要的问题就是:其他媒介公 信力会发生什么变化?用户如何评估社交媒体的公信力? 本文采用问卷调查法,通过网络调研平台采集数据,共获得来自北京、上海、广 州、成都四个城市的有效问卷 3284 份。研究分为两个部分:第一部分是纵向研究,将 2018 年的调查数据与 2009 年、2012 年的“中国传媒公信力”调查数据作对比,分析 9 年间中国媒介公信力的变迁情况。第二部分是横向研究,将社交媒体纳入媒介公信力的 测量范围,并通过回归分析、中介效应分析检验社交媒体对传统媒体公信力的影响。 研究发现:第一,由于媒介覆盖率的变化,手机、网络公信力上升,电视、报纸公 信力下降,手机公信力排名第一,打破了长期以来“电视第一”的媒介公信力格局。第 二,报纸覆盖率“断崖式”下跌,但公信力变化趋于平稳、呈“L”字形走势。第三,新 闻网站覆盖率普遍上升,官方新闻网站公信力回升,但商业新闻网站公信力逐年下降。 第四,微信在社交媒体中覆盖率最高、公信力最高,微信与传统媒介、新闻网站形成公 信力竞争格局。第五,社交媒体使用、社交媒体公信力对传统媒体公信力有正向影响, 社交媒体公信力是社交媒体使用影响传统媒体公信力的中介因素。

The measurements of media credibility are changing with time and the change of media ecology. On 2009, Sina Weibo launched as the beginning of social media development in China. On 2012, the WeChat Moments launched as the beginning of overall development period of Chinese social media. When social media develop into a new media unit, social media credibility and the changes of other media credibility are the most important issues. This study collected 3284 questionnaires by an online survey platform, including Beijing, Shanghai, Guangzhou, and Chengdu. This study is divided into two parts. The first part is the longitudinal study, which compares the 2018 survey data with the 2009 and 2012 survey data from the study of China's media credibility. Continuous survey data can reflect changes in media credibility over 9 years. The second part is horizontal study, which measures the social media credibility, and examines the influence of social media on traditional media credibility by regression analysis and mediation effects analysis. This study found that: First, due to the changes in media coverage, the credibility of mobile phones and Internet has increased, the credibility of television and newspapers has declined. The credibility of mobile phones has ranked first, breaking the long-standing situation of “TV first”. Second, the newspaper coverage has declined, but the change in credibility tends to be stable, showing an “L” development. Third, the coverage of news websites generally rised, and the credibility of official news websites picked up. However, the credibility of business news websites declined year by year. Fourth, WeChat is the highest coverage and the highest credibility in social media. WeChat competes with traditional media in media credibility. Fifth, social media use and social media credibility have a positive impact on traditional media credibility. Social media credibility is a mediate factor between social media use and traditional media credibility.