Method: Big-Data Analysis

# Method: Big-Data Analysis
## Public Policy Analysis: Perspectives and Methods (30700953)
### Yue HU

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## Overview

- What's "big" data?
- Big-data approaches
- Big-data problems

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# What's Big Data

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## Defining Big Data?

> Data sets characterized by huge amounts<sup>1</sup> of frequently updated<sup>2</sup> data in various formats<sup>3</sup>, such as numeric, textual, or images/videos.<sup>4</sup>

???

veracity: accuracy, integrity (how do you know?)  
value: how much value for each unit of data?

.bg-black.golden.ba.shadow-5.ph4.mt3[
.center[
Bottom Line

The ".red[Non]-data" data
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## Policy Analysis with Big Data

1. Data from e-government, civil service hotlines, government-citizen interactions
1. Official data from bureaus and departments
1. Speeches, statements
1. Traditional and new media
1. Official document archives
1. Judicial documents  
......
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1. Initiation of the agenda
1. Profile of policy makers
1. Policy making process
1. Logic of policy decisions and implementation
1. Policy evaluation
1. Prediction of policy outcomes  
......
]

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# Big-Data Approaches

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## Levels of Big Data Analysis

Description     
(Data science, the majority of big-data analysis)

&dArr;

Relationship analysis     
(Social science)

&dArr;

Pattern learning    
(Social science with other methods)

&dArr;

Causal inference
(Rare but growing)

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## Description

Global Covid-19

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Democratic Mood (Tai, Hu, & Solt 2022)

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## Relationship Analysis

???

1997

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## Pattern Learning

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## Causal Inference

Causal effect of the Confucius Institute Closure

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# Problems of Big Data

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## Issues about Big-Data Based Analysis

1. Analytic value
1. Ethics
1. Data representativeness
1. Pedagogical myth

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## Analytic value: Anything new?

[<img src="images/alreadyKnow1.png" height = 250 />](https://www.computerworld.com/article/3162030/microsofts-big-data-like-study-on-sleep-proves-what-doctors-already-know.html)
.center[[<img src="images/alreadyKnow2.png" height = 250 />](https://www.independent.co.uk/voices/gender-pay-gap-worst-offenders-government-targets-diversity-disability-equality-a8788341.html)]

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## Ethics: Where Are the Data from?

[.center[<img src="images/illegalCollection.png" height = 550 />]](https://www.ftc.gov/news-events/press-releases/2019/09/google-youtube-will-pay-record-170-million-alleged-violations)

???

FTC, New York Attorney General allege YouTube channels collected kids’ personal information without parental consent for targeting ads.

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## Ethics: What Are the Data Used for?

???

2018年FB数据泄露事件: 脸书2015年就发现英国剑桥分析公司“窃用”大量用户隐私数据用于投放政治广告，却为何没能及时告知用户、非等到媒体今年曝光才承认？

Cambridge Analytica助选

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???

Big-data kills

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## Data Representativeness

> To systematically characterize their views, we obtained a random sample of 9,911 social media posts from 2010 to 2015 ...... From these data, we .red[drew a sample] of 128 posts written by people ...... --- King, Pan, & Roberts 2017 *APSR*

> This analysis is limited to .red[the random sample] of tweets for which we collected hand labels, ......  ---Cirone & Hobbs 2022 *PSRM*

Not saying....

Sampling bias, provenance conflicts, increased fluctuations,  error rates...

???

provenance conflicts: source issue

Hansen, Lars Peter. 2019. “Purely Evidence-Based Policy Doesn’t Exist.” Chicago Booth Review. http://review.chicagobooth.edu/economics/2019/article/purely-evidence-based-policy-doesn-t-exist (March 27, 2019).

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## Pedagogical Myth

Typical conversation:

> A: I wanna use big-data method for my project. What should I do?  
> B: Go learn Python!!

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???

Difficult to change people's mind unless they want

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## Take-Home Points

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## Procedure

The presenters talk.

### Challenging (10min)

Drawing the Luck Dog

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*Process*

1. Presenters query.
    - A question about the paper
1. Challengers respond.
1. Challengers query.
    - A question about the presentation
1. Presenters respond.
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