CrissCross, CrossSolve and ZipZag
Origins of . . .
How did we get to CrissCross?
I began scaling assessments under physics teachers Jeff Funkhouser and Sheila Kolb when I started teaching in 1993 at Plano Senior High School. What began as simple grade frequency distributions calculated by hand evolved into entering scores into a TI graphing calculator to determine grade breaks, assessment averages, and minimum passing standards.
When I moved to Plano West Senior High School in 1999 to serve as Science Department Chair these methods expanded into deeper data analysis. I developed Excel spreadsheets that allowed for more efficient scaling adjustments and greater flexibility in determining grade thresholds. These tools also enabled our team to review assessment data collectively, leading to meaningful discussions about curriculum and instruction tied to each unit assessment.
On the evening of December 15, 2015, at Maggiano’s Italian Restaurant in Plano, I was seated next to Plano West AP Biology teacher Julia Drake at a celebratory dinner honoring Maggie Eichenlaub, Plano West’s office manager. During our conversation, Julia introduced me to ZipGrade, and a flood of ideas began forming. Prior to CrissCross, I would review assessments with my class, but only students who were invested in understanding their mistakes were truly engaged in the review. I needed a strategy that would actively involve all students in the review, allow them to learn from their mistakes and meet reteaching requirements. CrissCross was born. The current version available on www.GravityKills.net represents more than 100 iterations of refinement and improvement to the original spreadsheet.
My colleagues have been indispensable throughout this journey, particularly Jerry Grizzle. Jerry and I have taught physics together for over 20 years at Plano West before he moved to Richland High School in Prosper ISD in 2025 to serve as Science Department Chair. His willingness to embrace the most ambitious ideas and the partnership we’ve shared has meant a great deal. Through 2023, Jerry has served as a co-presenter and supported the delivery of the professional learning sessions listed below.
In 2016, Science Coordinator Karen Shepherd began hosting teacher-led professional development sessions, providing an opportunity to share these ideas more broadly. That year marked the first of many professional learning presentations focused on assessment, scaling, and instructional reflection.
PL Presentations
2016
Intro to ZipGrade
2017
2018
2019
2020
2023
2024
All my CrissCross, CrossSolve and ZipZag resources are available on my website www.GravityKills.net If you have any questions, please reach out - david.carroll@pisd.edu
What led to CrossSolve?
My physics tests have traditionally consisted of multiple-choice and free-response questions. While CrissCross increased student discussion and engagement with multiple-choice assessments, the free-response portion of the test remained largely unengaging.
For over 20 years, I administered a team-based free-response test for the final unit of each semester; however, the structure of this team assessment did not produce the same level of engagement as CrissCross. I experimented with allowing students to choose their own teams, forming teams based on ability level, open notes and open book but none of these approaches improved engagement. These methods often resulted in teams in which some members lacked basic foundational knowledge, leading to inequitable contributions toward completing the team test.
What was needed was an assessment that measured students’ basic foundational skills for the unit. These foundational skills are necessary for success on free-response questions and demonstrate to teammates that each student possesses the essential knowledge required to contribute meaningfully. Additionally, such an assessment helps build students’ confidence in their own abilities. This assessment is called Ticket to Team.
To increase engagement, students need time to process the assessment before participating in team discussions. Allowing each team member time to work independently ensures that every student has read through the test and begun formulating solutions. When it is time for team discussion, each member has something to contribute and is knowledgeable about the assessment
Student Benefits
Real-World & Future Relevance
It’s real-life: scientists and engineers work in teams, not in isolation
Returning college students report that many courses rely heavily on group projects
Collaboration & Communication Skills
Like CrissCross: team discussion and collaboration
Teach one another
Learn to interject and lead when necessary
Critical Thinking & Problem Solving
They develop the solutions
They have to debate and support their position
Student Growth & Mindset
Builds student efficacy – the ability to produce a desired or intended result
Builds confidence – students know they have the basic skills after passing Ticket to Team
Academic Performance
Encourages better performance on multiple-choice assessments – opportunity to reach a higher team
EB Student Benefits
Leverages Peer Interaction for Language Development
During group problem solving, EB students hear, practice, and negotiate academic language in meaningful contexts rather than through isolated drills.
Encourages Multiple Ways to Participate
CrossSolve does not require students to produce long verbal explanations. EB students can contribute through: pointing to diagrams, writing equations or steps, offering short phrases or keywords, confirming or questioning ideas
Builds Confidence and Academic Identity
Passing the Ticket to Team signals to EB students - “I belong in this academic space.”
Promotes Structured Academic Talk
Because teams must debate and support positions, students engage in purposeful discourse instead of casual conversation.
PL Presenation
2026
All my CrissCross, CrossSolve and ZipZag resources are available on my website www.GravityKills.net If you have any questions, please reach out - david.carroll@pisd.edu
Why ZipZag?
As school budgets tighten, finding ways to save money becomes increasingly necessary. Multiple-choice assessments can range from four to ten pages in length—amounting to nearly half a ream of paper per class period. Moving multiple-choice assessments online reduces paper usage and associated costs while also providing students with opportunities to practice taking online assessments, helping them become more comfortable with digital testing.
For teachers, ZipZag eliminates the need for physical test copies, is quick to set up, easy to manage, secure, saves paper, and easily integrates with CrissCross.
2026 PL Presentation
All my CrissCross, CrossSolve and ZipZag resources are available on my website www.GravityKills.net If you have any questions, please reach out - david.carroll@pisd.edu