Factorial Validity

class: center, middle, inverse, title-slide

.title[
# Factorial Validity
]
.subtitle[
## EDP 619 Week 6
]
.author[
### Dr. Abhik Roy
]

---

section {
    height: 600px;
    width: 60%;
    margin: auto;
    border-radius: 21px;
    background-color: #212121;
}

.remark-slide-container {
background: #212121;
}

.hljs-github .hljs {
    background: transparent;
    color: #b2dfdb;
}

.hljs-github .hljs-keyword {
    color: #64b5f6;
}

.hljs-github .hljs-literal {
    color: #64b5f6;
}

.hljs-github .hljs-number {
    color: #64b5f6;
}

.hljs-github .hljs-string {
    color: #b7b3ef;
}

.hljs-github .hljs {
    background: transparent;
    color: #b2dfdb;
}

.hljs-github .hljs-keyword {
    color: #64b5f6;
}

.hljs-github .hljs-literal {
    color: #64b5f6;
}

.hljs-github .hljs-number {
    color: #64b5f6;
}

.hljs-github .hljs-string {
    color: #b7b3ef;
}

section p {
    text-align: center;
    font-size: 30px;
    background-color: #212121;
    border-radius: 21px;
    font-family: Roboto Condensed;
    font-style: bold;
    padding: 12px;
    color: #bff4ee;
    margin: auto;
}

#center {
text-align: center;
}

#right {
  text-align: right;
}

.center p {
  margin: 0;
  position: absolute;
  top: 50%;
  left: 50%;
  -ms-transform: translate(-50%, -50%);
  transform: translate(-50%, -50%);
}

.center2 {
  margin: 0;
  position: absolute;
  top: 50%;
  left: 50%;
  -ms-transform: translate(-50%, -50%);
  transform: translate(-50%, -50%);
}

.tab {
    display: inline-block;
    margin-left: 40px;
}

.obr
{
 display:block;
 margin-top:-15px;
}
</style>

<div>
<style type="text/css">.xaringan-extra-logo {
width: 110px;
height: 128px;
z-index: 0;
background-image: url(/Users/skynet/Documents/WVU/Teaching/GitHub.nosync/edp619/static/img/course_hex.png);
background-size: contain;
background-repeat: no-repeat;
position: absolute;
top:1em;right:1em;
}
</style>
<script>(function () {
 let tries = 0
 function addLogo () {
 if (typeof slideshow === 'undefined') {
 tries += 1
 if (tries < 10) {
 setTimeout(addLogo, 100)
 }
 } else {
 document.querySelectorAll('.remark-slide-content:not(.title-slide):not(.inverse):not(.hide_logo)')
 .forEach(function (slide) {
 const logo = document.createElement('a')
 logo.classList = 'xaringan-extra-logo'
 logo.href = 'https://edp619.asocialdatascientist.com'
 slide.appendChild(logo)
 })
 }
 }
 document.addEventListener('DOMContentLoaded', addLogo)
})()</script>
</div>

---

class: highlight-last-item
layout: true

---

# Test Validity

---

## Definition

<center>
.bg-washed.b--light-red.ba.bw2.br3.shadow-5.ph4.mt5[
**Validity** tells you how accurately a method measures something
]
</center>

<center>
There are six main types
</center>

---

## Types

.pull-left[
 

Concurrent 
examines how well the results of a test approximate the results of another test

]

.pull-right[
 

Construct 
evaluates whether a measurement tool actually represents what it is intended to measure

]

.pull-left[

Content 
assesses whether a test is representative of all aspects of the construct

]

.pull-right[

Face 
considers how suitable the content of a test seems to be on the surface

]

.pull-left[

Factorial 
assesses the extent of correlation of the different factors with the whole test

]

.pull-right[

Predictive 
examines how well a test can forecast a concrete outcome

]

.footnote[You may see concurrent and predictive validity pooled together as criterion validity]

---

# Structural Ideas

---

## Constructs

<center>
.bg-washed.b--light-red.ba.bw2.br3.shadow-5.ph4.mt5[

**Constructs** aka ***latent constructs*** are variables that cannot be measured directly

</center>
]
</center>

<center>
some examples include
</center>

IQ


motivation


values

---

## Dimensionality

<center>
.bg-washed.b--light-red.ba.bw2.br3.shadow-5.ph4.mt5[

**Dimensions** of a data set are ideally the same as the number of columns - aka attributes 

</center>
]
</center>

<center>
however
</center>

some columns are copies, correlated, similar, useless, etc. so an actual count of dimensions may not be known

---

## Unidimensional Scales

.pull-left[
Cronbach’s `\(\alpha\)` is typically used to estimate internal consistency applied on a single latent construct (not necessarily one item!)
]

.pull-right[
aka unidimensionality
]

are used for measuring food preference (single latent construct) using participants' agreement with varying pizza toppings (three direct measures) 
 
 
--

Notice that the construct *is not* defined as pizza topping preferences

.footnote[*Pineapple is a hard no!*]

---

### A Bit More on Factorial Validity

- is used to probabilistically determine the way that the parts of the test are related to each other - aka its *internal structure*

- should match the actual, or *emperical* structure of the test

- in a nutshell it helps to nail down what a test measures by determining a probable number of dimensions needed to explain a construct

---

# Determining Factors

- Multiple methods can be used to determine

- We'll use the most common method known as a **Factor Analysis**, namely a type known as an **Exploratory Factor Analysis (EFA)**

---

# Stop!

If you do not know what covariance is or need a refresher, please go through this incredible video by [Josh Starmer](https://statquest.org/). If you are familiar, then please feel free to close out of this presentation and move on to the walkthrough

.center2[
 
 
 
 
 
<iframe width="670.2" height="330.6" src="https://www.youtube.com/embed/qtaqvPAeEJY" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen>
</iframe>
]

---

## Thats it!

If you have any questions, please reach out

<center>
<a rel="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/"><img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by-nc-sa/4.0/88x31.png" /></a> This work is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License</a>
</center>